Zlatan Ibrahimovic marked his return from suspension with a 94th-minute equaliser as Manchester United were held to a 1-1 draw with Everton on Tuesday on another frustrating night at Old Trafford.
Phil Jagielka's first goal in almost two years looked to have caused terminal damage to United's hopes of finishing in the Premier League top four.
But right at the death Ashley Williams handled a shot from substitute Luke Shaw and was sent off, allowing Ibrahimovic to send Joel Robles the wrong way from the penalty spot.
United might be 20 unbeaten in the league but it increasingly looks as if their best hope of qualifying for next season's Champions League now rests with winning the Europa League after a ninth home league draw of the season.
Wayne Rooney was left out of the United squad altogether, with manager Jose Mourinho saying that his captain was suffering with ankle problems.
Having dropped the underperforming Henrikh Mkhitaryan to the bench, Mourinho made clear that he expected better from his forward line following Saturday's 0-0 draw at home to West Bromwich Albion.
Ibrahimovic almost gave them the lift they needed in the first five minutes as he surged into the penalty area, but Williams thwarted him with a well-timed block.
United struggled to make headway, though, with only the odd glimpse of goal.
Ander Herrera planted a 20-yard shot wide from Michael Carrick's pass and Marcus Rashford saw a shot pushed aside by the advancing Robles.
The home side were shocked as Everton then took the lead in the 22nd minute, seconds after David de Gea had blocked Kevin Mirallas's near-post shot from a Gareth Barry chip-through.
From the resulting corner Williams glanced on and Jagielka, back to goal and under pressure from Marcos Rojo, somehow hooked the ball through the goalkeeper's legs.
United almost drew level on the half-hour mark after Mirallas conceded a free-kick by wrestling Jesse Lingard to the floor on the edge of the penalty area.
Daley Blind's curling shot was pushed out at full stretch by Robles, before Herrera smashed the follow-up against the bar from a tight angle.
Robles, criticised for his performance at Liverpool as Everton lost 3-1 on Saturday, was on form again to tip away Herrera's long-range strike later in the half.
Jagielka was equally sharp right on half-time with a well-timed challenge on Rashford, who burst into the penalty area onto Ibrahimovic's pass.
Mourinho brought on Paul Pogba for Blind at the start of the second half in an attempt to bring United back into the game, with Ashley Young switching to left-back and Herrera moving to the right.
It almost paid off within 10 minutes as the France international headed Young's free-kick against the bar.
Tempers boiled over as players from both sides squared up after a foul by Young on Mirallas, moments after the United player had been involved in a confrontation with Everton full-back Mason Holgate.
Despite that Pogba chance United began to look increasingly ragged.
Mourinho responded by throwing on Mkhitaryan and the previously out-of-favour Shaw, who got a big cheer as he made his first club appearance for a month.
Ibrahimovic thought he had equalised when he headed Herrera's right-wing cross beneath Robles with 19 minutes left, only for it to be ruled marginally offside.
Robles, under pressure from Ibrahimovic, then punched Pogba's diagonal ball straight to Marouane Fellaini, but the former Everton midfielder fired over.
Romelu Lukaku, quiet for most of the night, had a chance to score a late second for Everton on the break, but Eric Bailly made a fine challenge. It was to prove a costly missed opportunity.