Paris Saint-Germain took a huge step towards avoiding an embarrassing early exit from the Champions League and left Manchester United with work to do to reach the last 16 as Neymar scored twice in a 3-1 win at Old Trafford.
PSG, United and RB Leipzig are now all tied on nine points at the top of Group H with one game to go.
But the French champions are in the driving seat as they host eliminated Istanbul Basaksehir on Tuesday, while United need a point when they travel to Germany.
Ole Gunnar Solskjaer’s men were left to rue a host of huge chances early in the second half with the match poised at 1-1 after Marcus Rashford cancelled out Neymar’s early opener.
“We had some big chances, big moments and that’s the difference when you get to the big games,” said Solskjaer.
However, the United boss’ decision not to replace Fred before he was sent off seconds after Marquinhos scored PSG’s second was a naive mistake which cost his side.
The Brazilian midfielder had been lucky to escape a red card before half-time when he was only shown a yellow card after a headbutt on Leandro Paredes was reviewed.
“Fred shouldn’t put his head towards him, it’s either nothing or a red card, he’s a bit lucky to stay on,” conceded Solskjaer, who admitted to considering making a change at half-time.
“We spoke about staying calm, staying on your feet and the second one is nowhere near a yellow card.”
Leipzig’s late winner in a 4-3 thrillier in Istanbul earlier on Wednesday piled the pressure on PSG to win and keep their fate in their own hands going into matchday six.
The visitors started brightly in response and went in front after just six minutes when Neymar pounced on Kylian Mbappe’s deflected shot to drill low past David de Gea.
Fred’s first lucky escape came on 24 minutes as Italian referee Daniele Orsato decided a yellow card was sufficient after reviewing the headbutt incident.
Tuchel was furious when United needed just eight more minutes to make the most of that reprieve when Rashford’s shot took a wicked deflection off Danilo to wrong-foot Keylor Navas.
Fred was fortunate again moments later when he trod on Paredes, but it was the Argentine who was booked.
But if PSG’s luck was out before the break, they got the let-off they needed at the start of the second period through United’s profligacy.
Anthony Martial somehow blazed over with the goal at his mercy after brilliant work from Rashford and Edinson Cavani.
Cavani is PSG’s record goalscorer after scoring 200 times in seven seasons at the Parc des Princes, but the Uruguayan was allowed to leave for free when his contract expired in June.
The 33-year-old was inches away from exacting revenge with a delicate chip over Navas that came back off the crossbar before Marquinhos’s brave block denied Martial again.
Tuchel’s future as PSG boss would be plunged into doubt by a failure to progress from the group stage, but he made a telling contribution with a change of system to shore up his side’s susceptibility on the counter-attack as Ander Herrera and Mitchel Bakker were introduced.
De Gea produced an incredible save from Bakker low to his left, but that only delayed PSG retaking the lead by a few seconds as, from the resulting corner, the ball broke for Marquinhos to prod home from close range.
“We knew the little details would make the difference,” Marquinhos told RMC Sport. “They didn’t take their chances, we took ours and we are delighted tonight.
“In the second half, we had the courage and personality to play and take risks. The coach gave us confidence, telling us to take risks. It worked and we are really pleased.”
Less than a minute after the goal, United were finally down to 10 men as Fred’s luck ran out despite playing the ball before tripping Herrera.
United still came close to salvaging the point they needed to qualify as substitute Paul Pogba’s sweetly struck volley flew just over before Bruno Fernandes headed too close to Navas.
But PSG gained some measure of revenge for their stunning Champions League elimination to United in 2019 by sealing a huge win with a third in stoppage time when Neymar rolled home Rafinha’s cut-back.