Fred, who had already received a yellow card for headbutt on Leandro Paredes, continued to play through second half before being red-carded for a challenge in the 70th minute.
If Manchester United fails to advance in the Champions League, Ole Gunnar Solskjaer's decision-making could be as culpable as Fred's recklessness.
By the time Neymar scored Paris Saint-Germain's second goal to complete a 3-1 victory in stoppage time, Fred had long departed the Old Trafford pitch.
Not at a time of Solskjær’s choosing — as the manager repeatedly had the chance to do — but when the red card that seemingly had long been coming was finally shown with 20 minutes to go.
Fred could first have been dismissed around 30 minutes into this penultimate Group H match for thrusting his head toward PSG midfielder Leandro Paredes. To the disbelief of the French champions, the referee only booked Fred after reviewing the apparent headbutt on the pitch-side TV monitor.
With fans still shut out of Old Trafford because of ongoing coronavirus restrictions, there wasn't even any crowd to try to influence Daniele Orsato.
“There was only two choices," PSG coach Thomas Tuchel said, “either he did not touch him so it’s nothing, or he hit him and so it’s a red card.”
Even Solskjaer had expected to see Fred marching down the tunnel.
“He was lucky to stay on," Solskjaer said. "Fred knows he shouldn’t put his head towards someone, even though he doesn’t touch him.”
When the expectation might have been to make a substitution, Solskjær still had faith in Fred to return for the second half.
“Just be sensible,” was Solskjær's message to the Brazilian player at the break.
Perhaps, though, Marquinhos sending PSG into a 2-1 lead in the 69th minute was a chance to reconsider the decision and replace Fred?
But that decision wasn't taken and, within a minute, Fred was shown another yellow card, this time for a challenge on former United teammate Ander Herrera.
"He’ll hold his hands up and say sorry, but you can’t be sorry for winning the ball, can you?” Solskjær said. “It wasn’t a foul. Fred played really disciplined in the second half and when he makes a tackle like this, you can’t fault the boy.”
But it meant United's hopes of a comeback were impeded by being reduced to 10 men.
Losing at home after opening the campaign by winning the reverse fixture in Paris means the group is wide open with United, PSG and Leipzig only separated by goal difference. Only İstanbul Başakşehir is out of contention.
United, which missed out on the Champions League last season, needs at least a draw on Tuesday at Leipzig to advance to the round of 32.
“We know destiny is in our own hands," Solskjær said. "Big games are decided by fine margins and today they were against us.”
