He said: "The quality of the team is its strength and that includes mental strength. The players and the management team have a lot of character. You have to go from game to game and from strength to strength. That is how it is at this club.
"We have a lot of individual quality in the team but being a team is also important. We worked extremely hard together as Barcelona are not a bad team.
"They have not done brilliantly in the league but against us they really performed. It was hard work but we got a great result."
Van der Sar added: "I was pleased to keep two clean sheets against them because we always know we have a goal in us.
"Scholesy was brilliant in training before the game. We know he is always capable of scoring and is a great player."