The Dutchman struck three times against the Gunners.
"When I came here everyone talked about the biggest game of the year against Arsenal," Van der Vaart told the club's website.
"It doesn't matter if it's league or cup, it's always big and you have to win that one.
"Tottenham hadn't won at the Emirates and it was great feeling to go there and win in my first derby, and especially to score.
"We played a bad first half, went 2-0 down but in the second half we were a totally different team and that showed a lot of spirit."
Van der Vaart hailed the team's spirit again after coming from 3-1 down to draw 3-3 at the Lane.
"That felt a bit like a victory," he smiled. "It was a great game, an open game and both teams wanted to win.
"Like at the Emirates, we fought to the end and you could see with our fans that it was a fantastic night."