Real Madrid were 3-2 up at the Bernabeu when they saw Sergio Ramos dismissed for a challenge on Neymar, with Lionel Messi converting two subsequent penalties to complete his hat-trick and secure all three points for Barca in a 4-3 triumph.
The result leaves Atletico Madrid top of La Liga by virtue of their superior head-to-head record over Real - with the Madrid clubs just one point clear of Barca - and prompted Real star Ronaldo to allege Real were playing "against 12".
However, Xavi has defended referee Alberto Undiano, who had earlier awarded Real a debatable spot-kick that Ronaldo dispatched.
"Cristiano is wrong and his criticism is harsh," the 34-year-old said. "Barca were superior, we played better than Real Madrid and it shows in the result.
"As far as I’m concerned, they were all penalties, including the one from Dani Alves on Cristiano, from what I could see on the pitch."
Despite champions Barca hauling themselves back into the title race, Xavi does not consider there to be any favourites to lift the trophy.
"Atletico are the leaders and they’re a warrior-like team, they're battlers,” he added. "There are no favourites from now on though - there are three teams who can win the title."
