Redskins quarterback Alex Smith was sacked three times in the loss to the Colts. (Toni L. Sandys/The Washington Post)

The love affair was on last week for newcomers Alex Smith and Adrian Peterson. The duo got off to a strong start and helped the Washington Redskins to their first 1-0 start under Coach Jay Gruden.

The luster wore off Sunday.

The Redskins’ offense was horrid in a 21-9 loss to an Indianapolis Colts team not exactly known for its overwhelming defense. The running game was almost nonexistent, and the passing game struggled to incorporate its wide receivers for a second consecutive week. That equation produced zero touchdowns despite a pair of Andrew Luck interceptions that gave Washington good field position.

“We had no chemistry at all today,” Gruden said. “[Including] myself as a play caller, really. It’s my fault. I couldn’t get in any rhythm calling plays. Inside zone wasn’t working. Outside zone wasn’t working. Read-options weren’t working very well. Became one-dimensional. . . . We got sacked on two [play-action passes], for goodness sakes.

“Credit the defense. They out-executed us.”

The offensive numbers were ugly across the board. The Redskins converted just 5 of 15 third downs and were 0 for 2 in the red zone. They rushed for 65 yards on 22 carries. Slot receiver Jamison Crowder had a team-high 29 rushing yards on two attempts, including a 25-yarder. Peterson posted 20 yards on 11 carries, including a long of 14 yards, and never found enough room to start running downhill.

Smith completed 33 of 46 attempts for 292 yards, but most of his success came underneath and late in the game. Chris Thompson had a career-high 13 receptions for 92 yards.

“That was really complementary football,” Colts Coach Frank Reich said. “It was exactly the way you want to win, and the defense played so hard. They were swarming for the ball.”

The Redskins are thrilled to have Thompson, and he’s proving himself one of the best third-down backs in the league, but having him lead the team in receptions in consecutive weeks isn’t ideal. Paul Richardson, Josh Doctson and Crowder combined for 10 receptions, but only three of those came in the first half. The trio totaled eight receptions in the season opener.

Gruden credited the Colts’ defense for playing loose zones that took away the wideouts and most of the deep opportunities.

“Chemistry, rhythm, we didn’t have any of that,” Smith said. “Didn’t think we were great on first or second down. We gave ourselves some tough third downs in the first half and didn’t convert many of them. It was tough. Then in the second half we finally did get in a rhythm, but situationally, we put some drives together but would stall out. Stall in the red zone. Those were the two big things, looking at it, third down and red zone. One of the days where we weren’t going to have a ton of opportunities, but we needed to be better down there.

“They were playing pretty soft and weren’t going to give up big chunks, weren’t going to give up big plays. Make you check it down. They were going to rally and tackle, be disruptive up front. They did a great job of all those things.”

The offensive line is typically a unit the Redskins can rely on, but it also struggled. It opened few running lanes, and Smith was sacked three times. Mistakes were prevalent everywhere; both Doctson and Richardson dropped what would have been important third-down conversions. Even Dustin Hopkins missed a 49-yard field goal.

Thompson looked upset after the game and struggled to pinpoint what went wrong.

“They just played harder than us,” Thompson said. “We’ve all just got to find a way to be consistent. . . . I think our offense is way better than what we did today. There’s no way that we should ever finish a game not scoring a touchdown with the offense that we have. It’s just on us as the players to fix it.”

There was a lot of credit given to Colts defensive coordinator Matt Eberflus, who had been on the Cowboys’ defensive staff since 2011 before he took his first NFL coordinator job with Indianapolis. He had plenty of insight into what Gruden likes to do, and the scheme was similar to how Dallas has played the Redskins in the past.

Things need to get corrected quickly; the Redskins may need to score a bunch of points in the coming weeks, with opponents featuring quarterbacks Aaron Rodgers, Drew Brees and Cam Newton on the schedule.

“They prepared better than us. They played better than us,” guard Brandon Scherff said. “They did everything better than us.

“We’re just going to improve and figure out what we did wrong and move on from there. It’s only one game.”