Two late own goals left Manchester United work to do to reach the Europa League semi-finals as Sevilla salvaged a 2-2 draw from the first leg of their quarter-final tie at Old Trafford on Thursday.
United appeared to be cruising to victory through two goals from Marcel Sabitzer inside the opening 21 minutes.
But the loss of centre-backs Raphael Varane and Lisandro Martinez to injury proved costly as Tyrell Malacia and Harry Maguire deflected balls into their own net in the final six minutes plus stoppage time.
United will also have to cope without Bruno Fernandes for the second leg on April 20 after he picked up a yellow card that leads to a suspension.
"We conceded two own goals, bad luck, and we have to deal with it," said United manager Erik ten Hag. "We have to learn to kill the game, but still everything is open."
The home side were without 28-goal top scorer Marcus Rashford due to injury, but still made light work of the Spaniards before half-time as Sabitzer struck twice.
Anthony Martial's return for injury is a timely boost for Ten Hag with Rashford set to be sidelined for a few weeks.
The Frenchman has been a peripheral figure since the Dutchman took charge, but Ten Hag said on the eve of the game that his side play their best football with Martial up front.
So it proved as Martial's hold-up play eventually saw the ball worked to Fernandes, who fired a ball into Sabitzer's feet and the on-loan Bayern Munich midfielder coolly slotted past Bono.
Just a few moments later Sabitzer, who had scored only once for United in 12 previous appearances, netted his second. Martial was this time the creator with a perfect pass through for Sabitzer to again leave Bono in the Sevilla goal with no chance.
Casemiro's first appearance for nearly a month due to a four-game Premier League ban added authority to the United midfield and the Brazilian should have marked the occasion with a goal after more good approach play by Martial.
Martinez concern
Sevilla are fighting a relegation battle in La Liga and it showed until a late flurry as they only briefly threatened to bring the tie to life.
Tanguy Nianzou's powerful header in first-half stoppage time was saved by David De Gea before Varane completed the clearance off the line.
Antony came closest to adding to United's lead in the second half when the winger struck the inside of the post with Fernandes begging for a pass in a better position.
Malacia should also have done better when teed up by Wout Weghorst in acres of space inside the Sevilla box.
Ten Hag showed his thoughts were already turning to a trip to Nottingham Forest in the Premier League on Sunday as Fernandes and Martial made way in the final half-hour.
That decision proved costly as Malacia dallied to allow Jesus Navas to pounce inside the United box, the former Manchester City winger's cross deflecting off the Dutch left-back to wrong-foot De Gea.
Martinez then pulled up with a what looked like a concerning Achilles injury and had to be helped from the field by fellow Argentine World Cup winners Marcos Acuna and Gonzalo Montiel.
United had already made their five substitutions so ended the game with 10 men and could not hold on.
De Gea produced a brilliant save to deny Youssef En-Nesyri an equaliser.
But United's reprieve only lasted seconds as another En-Nesyri header cannoned off Maguire and into the net in the 92nd minute.