Rayan Cherki struck in injury-time to earn Lyon a draw at home.
Fonseca said afterwards: “I said to my players that I’m really proud of them, the courage they showed and how they played the game – imposing our game without being afraid of anything.
“We showed a lot of quality. For that, I’m happy with the team, with the players – but I’m not totally happy with the result. We can do better, but we cannot forget that we’re playing against Man Utd, a team that’s really efficient in attacking transitions."
On Cherki's late goal, Fonseca added: “It’s really important – firstly because this team showed that they never give up.
"We've kept the second leg open. We know it’ll be really difficult but, after what we showed here tonight, we still have a chance.”