In winning its 12th straight game in all competitions, the English Premier League leaders tied a Champions League record for the margin of victory held by Juventus for its victory over Greece's Olympiakos in 2003.
The Gunners, who were every bit as good as the score indicated, got two goals from Cesc Fabregas, two from 18-year-old Theo Walcott, one from Alexandr Hleb, an own goal and a late tap in from substitute Nicklas Bendtner.
"We wanted three points and to play well but you can't predict that," said Arsenal manager Arsene Wenger. "Everything went for us."
Arsenal put on a show at the start of the second half, scoring three goals in 13 minutes to double its lead.
Fabregas' second goal was a thing of beauty, set up by a long run by Hleb from deep in the Arsenal half, a dummy by Emmanuel Adebayor and pass from the brilliant Walcott to Fabregas charging into the box.
Wenger tried to downplay the spectacular performance by his young team.
"Yes it was a complete team performance," he said, "but we are a young team and can still improve. There is still more to come from this team. Can we keep our humility and feet on the ground? Can we continue to enjoy what we do? If we do, I feel we can develop. We have seen some great performances, but still everyone is improving."