Redskins tight end Jordan Reed scores a touchdown before halftime to give Washington a 21-0 lead. (Ricky Carioti/The Washington Post)

Here are four takeaways from the Redskins’ 24-6 win over the Cardinals in the season opener. 

Jay Gruden finally gets a Week 1 win: Gruden stressed the importance of a fast start this season given what figures to be a difficult schedule ahead after next week’s home opener against the Colts. The Redskins, who were outscored 102-49 in Gruden’s previous four season openers, all losses, responded with perhaps their most dominating first half of Gruden’s tenure. Offensively, the only team that could stop Washington in the first half was Washington.

After a couple of penalties moved the Redskins out of field goal range on their first possession, Washington mounted three consecutive touchdown drives of at least 10 plays. The Redskins outgained Arizona 261-36 in the first half, during which they made 22 first downs to the Cardinals’ two.

The Redskins’ defense came to play: A late touchdown run by David Johnson denied Washington its first shutout since a 23-0 win over the Eagles on Sept. 30, 1991, but Greg Manusky’s defense took away everything the Cardinals wanted to do for three-plus quarters. Johnson gained 23 yards on his first three carries, but Washington, which ranked last in rushing defense a season ago, limited him to 14 for the remainder of the game.

Led by Quinton Dunbar, who had the game’s only interception, the Redskins’ secondary made open-field tackles to end Arizona drives and broke up five Sam Bradford passes. The Cardinals’ quarterback looked lost for much of the day, finishing 20 of 34 for 153 yards.

Alex Smith makes strong first impression: So much for needing a few quarters to find a rhythm after attempting only 14 passes in the preseason. Smith was sharp from the start on Sunday, completing 17 of 20 passes for 171 yards and two touchdowns in the first half to help stake Washington to a 21-0 lead. Smith showcased all of the skills that have the Redskins confident in the offense taking a step forward after letting Kirk Cousins walk in free agency.

On Washington’s second first-half touchdown drive, Smith picked up a fourth down on a QB sneak, found Jordan Reed for a 22-yard completion after spinning away from pressure, scrambled for seven yards and threaded the needle on a pass to Jamison Crowder.

Adrian Peterson and Chris Thompson run wild: Peterson, playing in his first regular season game since he rushed for 79 yards with the Cardinals last November, finished with 96 yards on 26 carries and added 70 yards receiving on two receptions. He passed Jim Brown for 10th-place on the all-time rushing list and scored his 100th career rushing touchdown in the process.

Thompson reportedly isn’t back to 100 percent after sitting out the preseason, which is scary news for Washington’s future foes. In his first game since injuring his knee in Week 11 of last season, Thompson had 65 yards rushing on six carries and another 63 yards on a team-high six receptions. If Sunday was any indication, for as long as Peterson and Thompson remain healthy, the Redskins’ offense should be one of the better units in the league.

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Final: Redskins 24, Cardinals 6

Alex Smith passed for 255 yards and running backs Adrian Peterson and Chris Thompson combined for 294 total yards as Washington gave Coach Jay Gruden his first Week 1 win in five tries.

4th Quarter

Sloppy finish: With Washington looking to burn the clock after the two-minute warning, Adrian Peterson turned a dump-off pass from Alex Smith into a 52-yard gain before fumbling while fighting for extra yardage. The Cardinals recovered, resulting in the Redskins’ first turnover the game, but gave the ball right back six plays later when Matt Ioannidis recovered his strip sack of Sam Bradford with nine seconds to play. (Redskins 24, Cardinals 6)

Fourth-down drop . . . and stop: Ricky Seals-Jones couldn’t handle a Sam Bradford pass in the end zone, turning the ball over on downs to the Redskins with 3:20 to play. That should just about do it. (Redskins 24, Cardinals 6)

Cardinals in business again: It’s probably too little too late for Arizona, but a long punt return by Christian Kirk after a three-and-out by the Redskins has the home team in the red zone with under four minutes remaining. Washington’s offense hasn’t been nearly as sharp in the second half as it was in the first 30 minutes. (Redskins 24, Cardinals 6)

There goes the shutout: Jinx? David Johnson plowed into the end zone late in the fourth quarter, extending the Redskins’ shutout-less streak another game. Sam Bradford overthrew Christian Kirk on the Cardinals’ ensuing two-point conversion attempt and it remained a three-score game. (Redskins 24, Cardinals 6, 5:47 4th Quarter)

Dustin Hopkins extends Washington’s lead: Dustin Hopkins drilled a 31-yard field goal early in the fourth quarter to give the Redskins a 24-0 lead. If you’re wondering, Washington’s last shutout was in a 23-0 win over the Eagles on Sept. 30, 1991. Meanwhile, wide receiver Trey Quinn, who injured his ankle in the third quarter, has been ruled out for the remainder of the game. (Redskins 24, Cardinals 0, 12:13)

3rd Quarter

Quinton Dunbar gets a pick: Quinton Dunbar adds to his already strong game by intercepting Cardinals quarterback Sam Bradford with 1:55 to play in the third quarter. The pass was wildly overthrown and if Bradford keeps playing like this, the Redskins might see rookie Josh Rosen before the game’s over. (Redskins 21, Cardinals 0)

Redskins’ drive stalls: A holding penalty on Trent Williams, Washington’s seventh penalty of the game, derailed a promising drive with less than five minutes remaining in the quarter. The Redskins did manage to burn nearly seven minutes off the clock, and with a three-touchdown lead, the clock is their friend. (Redskins 21, Cardinals 0)

Trey Quinn leaves with an injury: Wide receiver Trey Quinn, the final pick in this year’s draft, injured his ankle on a punt return early in the third quarter. Quinn, who was carted to the locker room after being examined on the sideline, is listed as questionable to return.

The boo birds are out in Arizona: Cardinals fans are letting their team hear it and for good reason. Arizona was forced to punt again after Sam Bradford overthrew wide receiver Chad Williams on third down with 11 minutes remaining in the third quarter. The Cardinals are 0 for 5 on third down. One play earlier, Quinton Dunbar broke up a deep pass intended for Larry Fitzgerald, who has been limited to two catches for 30 yards. (Redskins 21, Cardinals 0)

Alex Smith avoids a safety: The Redskins’ seemingly infallible offense regressed a bit on Washington’s first drive of the second half. Backed up at their own 8-yard line, Adrian Peterson ran for a loss of four yards. After a rare Alex Smith incompletion, the Redskins’ quarterback was in danger of being sacked in the end zone for a safety when he flipped the ball underhand across the goal line. Officials conferred to determine whether to call intentional grounding, which also would’ve resulted in a safety, but ultimately ruled that Josh Doctson was in the vicinity. (Redskins 21, Cardinals 0)

Another Cardinals punt: Arizona gained nearly as many yards on their first drive of the third quarter (34) as they did in the entire first half (36), but the possession ended with another Andy Lee punt. Redskins linebacker Josh Harvey-Clemons broke up Sam Bradford’s third down pass intended for David Johnson. Bradford, like most of the Cardinals, has had a rough afternoon, with 44 yards on 5 of 10 passing. (Redskins 21, Cardinals 0)

Halftime: Redskins 21, Cardinals 0

With the exception of a couple of penalties that ended their first drive, the Redskins could not have played a better half of football. They outgained the Cardinals 261-36, picked up 22 first downs to Arizona’s two and generally did whatever they wanted on offense. Alex Smith is 17 for 20 for 171 yards and two touchdowns, while Chris Thompson has 90 total yards and a score. Adrian Peterson looked strong as well, rushing for 53 yards and a touchdown on 14 carries against his former team. Can they keep it up?

2nd Quarter

Redskins add another touchdown before halftime: Who are these guys? The Redskins extended their lead to 21-0 on Alex Smith’s second touchdown pass of the game, a 4-yard completion to Jordan Reed, who extended the ball across the goal line to cap a 10-play, 92-yard drive before halftime. (Redskins 21, Cardinals 0, :08 2nd Quarter)

Who needs WRs?: Alex Smith is 12 for 15 for 142 yards and he’s completed only three passes to his wide receivers. Chris Thompson has a game-high five catches for 55 yards and Adrian Peterson’s first catch just went for 18 yards, moving Washington to the Arizona 44 at the two-minute warning. (Redskins 14, Cardinals 0)

The Redskins are dominating this game: After Arizona’s second consecutive three-and-out, the Redskins have run 34 offensive plays to the Cardinals’ 13 and are enjoying a 13-minute advantage in time of possession. First downs are 15-2 Washington. With 3:27 remaining in the half, the Redskins have plenty of time to add to their lead, but they’ll start from their own 8-yard line. (Redskins 14, Cardinals 0)

Adrian Peterson extends Redskins’ lead: With backup linebacker Ryan Anderson leading the way in the fullback role he played a few times last season, Adrian Peterson burst into the end zone on third-and-goal from the Arizona 1 to give the Redskins a two-touchdown lead. Peterson’s 100th career rushing touchdown ties him with Marshall Faulk and Shaun Alexander for the seventh-most rushing touchdowns in NFL history. Alex Smith was the key to Washington’s 15-play, 73-yard drive. He picked up a first down on fourth-and-short from midfield on a QB sneak, found Jordan Reed for a 22-yard gain after looking off his first two reads and spinning away from pressure to extend the play and made a quick decision to pull the ball down and run later in the drive. (Redskins 14, Cardinals 0, 4:10 2nd Quarter)

Defense forces a three-and-out: After Chris Thompson gave the Redskins the lead, the Redskins’ defense gave the ball right back to Alex Smith and the offense. Former Cardinals safety D.J. Swearinger made the key play, breaking up a third-down pass intended for tight end Ricky Seals-Jones. (Redskins 7, Cardinals 0)

Redskins strike first on Chris Thompson TD catch: On the first play of the second quarter, Alex Smith found Chris Thompson in the flat and the Redskins’ running back did the rest, scampering 13 yards into the end zone to break a scoreless tie. Thompson’s touchdown capped an 11-play, 80-yard drive, with all but 22 of those yards coming on the ground. (Redskins 7, Cardinals 0, 14:54 2nd Quarter)

1st Quarter

Washington’s running game is rolling: Word is that Chris Thompson isn’t back to 100 percent after his offseason knee surgery. What is he, 99 percent? Thompson, who had a catch for a first down on the Redskins’ first drive, has ripped off runs of 13 and 14 yards on Washington’s second possession. Three strong runs by Adrian Peterson, including one that moved him past Jim Brown on the all-time rushing list and another to pick up a first down on third-and-short out of a timeout, has the Redskins in the red zone as the first quarter comes to an end. (Redskins, 0, Cardinals 0)

Quinton Dunbar tackle forces a Cardinals punt: Arizona picked up a couple of first downs on its first drive on runs by David Johnson, but the Redskins forced Andy Lee’s first punt of the afternoon with back-to-back impressive open-field tackles. Josh Norman dropped Johnson for a short gain after a catch in the flat on second down before fellow corner Quinton Dunbar stopped rookie Christian Kirk one yard short of the sticks on a pass over the middle. Tackling was a problem for Washington at times during the preseason. It’s early, but Greg Manusky’s unit is off to a solid start. (Redskins 0, Cardinals 0)

Redskins’ opening drive stalls: Washington moved the ball on its first possession, with Adrian Peterson picking up 12 yards on three carries and Alex Smith completing a 16-yard pass to tight end Jordan Reed on a seam route. A 15-yard personal foul penalty on Cardinals safety Tre Boston for hitting a defenseless receiver (Reed) had the Redskins in business in Arizona territory. Then Washington shot itself in the foot, first with a false start penalty on Trent Williams on first down and then an intentional grounding penalty on Smith, who was pressured by Deone Bucannon, that backed the Redskins out of field goal range. Tress Way punted the ball away with 10:13 to play in the quarter. (Redskins 0, Cardinals 0)

Underway in the desert: After Arizona won the toss and elected to defer to the second half, Redskins rookie free agent Danny Johnson returned the opening kickoff to the 23-yard line. Team captain Alex Smith and the offense will take over from there.

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