Manchester United is on to the Europa League final, and for much of Thursday evening’s semifinal second leg against Celta Vigo at Old Trafford, that looked like a foregone conclusion. In the end, it was anything but.

Marouane Fellaini’s 17th-minute header had the Red Devils cruising with a 2-0 aggregate lead and with preliminary travel plans in place for a trip to Stockholm to face Ajax. Then the game descended into chaos. Facundo Roncaglia equalized for Celta. Moments later, a scuffle resulted in two red cards (and probably should have had a third) to set up a dramatic finish.

With Eric Bailly and Roncaglia gone and Antonio Valencia fortunate to still be on the pitch, the game moved into six minutes of extra time as Celta Vigo sought one more goal to flip the tie and progress on away goals. The Spanish side conjured up an astonishingly good chance to shock Old Trafford. The chance fell to former Manchester City striker John Guidetti, who had been at the heart of the skirmish just minutes earlier. And Guidetti … well, he’ll see the missed chance in his nightmares for weeks to come.

The final whistle sounded two seconds after Guidetti’s mishap. Celta players sunk to the turf in disbelief. Home fans exhaled. Jose Mourinho hugged assistants and held the embraces just a second or two longer than usual.

Thanks to a 2-1 aggregate victory, Man United is moving on to the May 24 final in Stockholm. But not without a scare.

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“Today we suffered,” United midfielder Ander Herrera told BT Sport after the match. “They were playing the game of their lives.”

The suffering, in the end, paid off. Just barely.

United had looked comfortable for the vast majority of the evening after Fellaini’s opener.

The goal provided interesting insight into how atypical a midfielder Fellaini is, and how United alters the way it plays based on his strengths. Fellaini played a forward pass to start the move, and as the ball drifted out wide to the left, Fellaini found himself in a standard position for a central midfielder.

Immediately when space opened up for a cross, however, Fellaini sped forward, angling his run toward the far side of the box. The problem was that, initially, the cross didn’t come.

The Red Devils recycled the ball through Ander Herrera. With Pogba joining the first stage of the attack and Fellaini hoping to get involved in the second stage (and hoping to get on the end of a ball into the box), United’s attack almost broke down because Herrera had no options in the middle of the park.

In fact, it looked like the attack had fizzled out. The Old Trafford crowd groaned. But United overloaded the left side, Celta Vigo couldn’t get a tackle in, and eventually Rashford checked back into space to receive the ball. He had time to pick his head up, and when he did, he saw that Fellaini had stayed forward. That left him with no second thoughts.

Fellaini’s positioning on the play was a gamble — just like a striker sneaking into a position for a rebound rather than offering an option for a player with the ball. As a central midfielder, opportunities to affect the game as an aerial target don’t come naturally, so Fellaini strays from the natural pattern of a game to put himself in dangerous, even if sometimes awkward, positions. It’s a risk because Fellaini’s lack of availability for a short pass could have destroyed the sequence. But because United was able to play out of the pickle, it was able to put Fellaini’s unique talent and role to good use.

Fellaini performed his defensive duties excellently for much of the match as well, and his presence was crucial during long spells of Celta Vigo possession. The visitors had around 70 percent of the ball throughout the first 10 minutes of the match, but they couldn’t do much with it. The Fellaini-Pogba-Herrera midfield trio kept play in front of them. Celta’s wingers came infield to overload the deep central portion of the attacking third, but penetration was rare. The Spanish side tested United goalkeeper Sergio Romero on several occasions, but never really troubled him.

The most eye-catching moment of the first 15 minutes was an absurd sequence of skill from Pogba. He evaded two opponents with four touches – and without the ball touching the ground.

That moment, and the chance at the tail end of it, were the most eye-catching things United did over the first 15 minutes. Henrikh Mkhitaryan went on a few dazzling runs as well, and a few crosses narrowly evaded United’s forwards. But clear-cut chances didn’t materialize until Fellaini’s goal.

Celta Vigo’s two best chances to cut its aggregate deficit in half came on headers, one on either side of halftime. In the 42nd minute, Pione Sisto sent in a left-footed cross that found the noggin of Daniel Wass, but the pace and location of the ball prevented Wass from directing it toward goal. Guidetti had a better chance in the second half, but he flubbed his effort wide.

A third headed chance finally bore fruit. Celta attackers outnumbered United defenders in the center of the box as the Red Devils scrambled to defend a short corner, and Roncaglia’s flick glanced in off the post.

Less than two minutes later, players swarmed to an incident near the center circle. Guidetti threw himself to the pitch after Antonio Valencia’s arm or hand made contact — the extent and force of which was debatable — with Guidetti’s chest. Bailly and Roncaglia were certainly involved in the scuffle, but neither appeared to do anything particularly flagrant. Nonetheless, both were dismissed, and Bailly will miss the final, provided a potential appeal of the red card is not successful.

In the end, United avoided conceding a second by ever so thin margins and advanced with hearts in mouths. After Sunday’s loss to Arsenal, a top-four Premier League finish is looking more and more unlikely, and therefore the Europa League is looking more and more like the Red Devils’ only route to next season’s Champions League.

Thursday’s win kept that route as a viable one, and it ensured Mourinho’s men will have everything to play for in the finale in two weeks time.

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