The Russians roared into a 3-1 lead, but were ultimately pegged back to a 3-3 draw which took the Reds through to the last 16 of this season's Champions League.
"We knew it was a big game for them and we expected them to try to impress and they did that," Fletch told MUTV. "We had a lot of chances and feel we should have won the game, but they deserve credit for scoring three goals at Old Trafford. The character we showed to come back and get that point was brilliant.
"It's always disappointing to concede goals and that can't be overlooked, but the character we showed to come back from 3-1 down was really important."