Manchester United defender Nemanja Vidic admits he was impressed by Besiktas after Tuesday's 1-0 win in Istanbul.
The Serbia international said: "Besiktas are a very good team and play a great brand of football.
"I must say they gave us a big test. On the field, they were the equal to us. However, we had that little extra quality and left with the three points."
Vidic added: "I think for the other teams in our group, they will find it very difficult here. Their fans never shut up!!"
