The Serie A side sensationally dismantled United on the banks of Lake Como, with a double from talisman Nico Paz, and goals from Tasos Douvikas and Jacobo Ramon putting the hosts 4-0 up with 10 minutes left to play.
The final result is Como's second 4-1 win Europe this season, and the former Arsenal and Chelsea playmaker admitted he was thinking ahead to the weekend clash with Sassuolo as United floundered late on.
"I regret maybe the last 10 minutes as I was the one telling the team to slow down, because we have another game coming up, and maybe with a 4-0 lead we could have managed things better.
"I told Douvikas not to run anymore, to stay in the middle and maybe that's what I regret, because I’m the first one who always pushes the fight until the end. That goal from United hurt me."