Blues winger T.J. Oshie is sandwiched between Washington’s Julien Brouillette and goaltender Braden Holtby in the second period. Despite Tuesday’s win, Washington could find itself eliminated from playoff contention by Thursday. (Jasen Vinlove/USA Today Sports)

For so long this season the Washington Capitals have needed games like Tuesday night, with their top players setting a tone, the entire roster contributing to the defensive effort and their goaltender providing a solid backbone.

Squaring off against a St. Louis Blues squad in contention for the Presidents’ Trophy as the NHL’s best team in the regular season, the Capitals engineered one of their most complete games in a 4-1 win at Scottrade Center.

Alex Ovechkin recorded three points, including a goal to make him the first and likely only player in the NHL to reach the 50-goal plateau this season, Nicklas Backstrom posted his first two-goal game since Nov. 1, Braden Holtby finished with 28 saves and the Capitals overcame an injury-ravaged blue line. But for as thorough as the victory was, the Capitals’ playoff hopes remain increasingly slim.

Wins by Columbus and Detroit on Tuesday night mean the Capitals could be eliminated before they play again Thursday. Even if Washington were to win each of its final three games, any two points gained by the Blue Jackets combined with any single point earned by the Red Wings over those teams’ final three games would eliminate Washington. Both play Wednesday.

“We obviously need [wins] but the bigger picture throughout the year was that we didn’t have enough of these [performances] in a row,” said Holtby, who was making consecutive starts for the first time since March 5-6. “We had them spotted throughout and that’s what got us to this place we’re in right now. All we can do is play the last three games as hard as we can.”

The Post Sports Live crew debates whether General Manager George McPhee or Coach Adam Oates is more to blame for the team's performance. (Post Sports Live/The Washington Post)

Facing one of the stingiest defensive teams in the NHL — St. Louis entered the contest allowing the third fewest goals (2.23) and shots (26.5) against — the Capitals needed a sturdy start they could build off of at the very least. While there were breakdowns, Washington delivered with crisp passes and solid backchecking from the opening faceoff.

Holtby handled a few quality chances, with the two best coming from T.J. Oshie, as the first period progressed to keep the game scoreless. First there was Oshie’s backhander off a rebound with more than eight minutes remaining in the period that Holtby kicked aside with his left pad and then, with less than five minutes to go in the first, he turned away a wide-open, point-blank one-timer from the Blues forward in the slot.

Ovechkin drew a hooking penalty on Derek Roy that paved the way for his 50th goal and an initial lead.

“I thought we came out [and] did a good job,” Coach Adam Oates said. “Scoring first certainly helps, but right from the start of the game it felt like the guys were ready and doing the right thing.”

Ovechkin blasted his familiar one-timer from the left circle above Ryan Miller’s left shoulder to make it 1-0 Capitals with 17 minutes 54seconds gone in the first. It made him just the 11th player in NHL history to record 50 goals in five different seasons, joining a cast of Hall of Famers that includes Wayne Gretzky, Mario Lemieux, Mike Bossy, Marcel Dionne, Guy Lafleur, Phil Esposito, Bobby Hull, Brett Hull, Pavel Bure and Steve Yzerman.

“It means a lot. It’s big number and it’s going to be in history for my whole life,” Ovechkin said, but the star winger was more focused on the team’s postseason hopes than his personal milestone. “We understand the situation right now and unfortunately Columbus win, but we still have chances and we’re going to fight through it. If we going to make it we going to make it. If not, we just have to finish on the right note.

Maxim Lapierre tied the contest with 2:39 gone in the second and St. Louis began to bring the full force of its dominant possession style in the minutes that followed drawing two separate penalties against rookie Evgeny Kuznetsov. Troy Brouwer managed to negate half of the lengthy penalty kill, though, when he drew a slashing call on Kevin Shattenkirk on a shorthanded breakaway.

That penalty proved critical as Mikhail Grabovski went on to rip a heavy shot past Miller short side to re-establish the lead, 2-1, during the four-on-four play.

Grabovski’s goal, his first since returning from injury five games ago, offered a boost for the visitors. The Capitals settled back into a steady rhythm, managed St. Louis’s waves and with 70 seconds remaining in the middle stanza Backstrom scored his first goal to make it 3-1.

It was a pretty play off the rush, and a reversal of roles for Washington’s franchise players as Ovechkin carried the puck down the right wing and then dished it to center ice where Backstrom fired a one-timer past Miller (18 saves).

While two-goal leads haven’t been all that comforting for the Capitals — they’ve coughed up 13, six in the third period alone — Backstrom offered some extra insurance on the opening shift of the third. Showing remarkable patience upon receiving the puck on the power play, Backstrom moved in toward the hash marks on the right side and then shot through a screen to put the Caps up 4-1 just 16 seconds in. The margin held but whether it will matter in Washington’s quest to reach the postseason is uncertain.

“We’re obviously in a tough position but we only can control ourselves,” Backstrom said. “We’ve just got to focus on — we have three games left, take those three games see what we can do and we’ll see what happens with the other teams.”