De Gea made a good save from Mbappe's header but, from the resulting corner, PSG took the lead when United left Kimpembe unmarked to volley home.
Despite the incredible pass from Di Maria, Mbappe simply stole the show on the goal.
David De Gea has been in superb form of late in the Premier League and has kept back to back clean sheets against Leicester City and Fulham.
Check out 90min's breakdown of the game below.
United were impressive in the first half, without creating much in front of goal.
Solskjaer is not only winning games like a United manager is expected to win, he is also talking and acting like one.
United will be without Paul Pogba in the second leg next month in Paris after he received a second yellow card in the 89th minute for a lunge on Dani Alves. Meanwhile, Anthony Martial keeps his place in the side, with Alexis Sanchez still benched. If anyone deserves credit, it is Nemanja Matic for the way he stifled Julian Draxler by breaking up PSG attacks time and again during the first half.
Grammys 2019: Joy Villa dresses as Trump's border wall on red carpet
Villa , an outspoken Trump supporter, has become known for using her Grammy looks to make pointed statements. She carried a "Make America Great Again" bag alongside her silver dress with barbed wire on her shoulders.
United were 11 points off fourth place when Mourinho was sacked, but the side has only dropped two points since then.
Di Maria was the star of the match when he assisted twice for PSG's two-nil win over Manchester United in the first leg of the Champions League. Over in Paris, the suits would have been smiling and clinking champagne glasses at seeing another routine passage to the quarter-finals.
Marquinhos was excellent for the men from the French capital against United.
Reaction to Ashley Young's one-year contract extension may have been lukewarm last week, but Manchester United fans are now showering their defender in praise following an incident with Angel Di Maria.
See how to watch and follow live updates from the game here.
Porto have won their last five Champions League matches to match a club record and claimed 16 points - more than any other team in the group phase.
The teams will face off March 6 in the second leg of their round-of-16 series.