Arsenal boss Arsene Wenger believes winning five trophies this season is not beyond Manchester United, even though they surrendered two away goals in their 2-2 draw with Porto.

Wenger insisted: "An impossible task? No, because United have enough quality to go to Porto and win. But Porto is a difficult place to go. We had them in the group. They have the culture of regularly being in the Champions League. But it is not impossible for Manchester United."

Wenger added: "Tiredness is more mental than physical. Sometimes when players come in to the team they look as tired, if not more tired, than the players who played the game before. It is very unpredictable.

"Offensively we have plenty of solutions. I have not decided yet who will be rested or not. But we always try to rotate a bit without destroying the balance of the team."