Having kicked off Group H with a 2-1 win in the French capital and 5-0 shellacking of RB Leipzig, Ole Gunnar Solskjaer’s side knew they would go through to the round of 16 if they avoided defeat on Wednesday.
United looked well placed to secure that vital point after Marcus Rashford cancelled out Neymar’s early stunner, but Marquinhos and Neymar goals either side of Fred’s belated sending off saw PSG run out 3-1 victors at Old Trafford.
Mbappe and Neymar continued to prove a handful, with the latter passing for Florenzi to send over a cross that Marquinhos met with a header that clipped the crossbar.
De Gea tipped a low effort from Mitchel Bakker around the post and fellow substitute Ander Herrera made an impact from the resulting corner, with the former United midfielder hitting a wayward strike that Abdou Diallo turned across for Marquinhos to steer home.
Matters soon worsened as Fred finally got the red card he had been threatening to collect all night, although he appeared to get the ball in the challenge that finally brought his marching orders.
Substitute Paul Pogba went close with an outstanding strike and Fernandes’ near post header was saved as depleted United pushed, only to be caught cold at the end as Rafinha cut back for Neymar to turn home in stoppage time.