Real claimed they deserved two penalties in the 2-1 defeat.
"We witnessed a great match and the best team won," said Xavi.
"Alexis is a great player, very important for us, and I have a lot of confidence in him. This goal will give him a lot of confidence.
"A six-point advantage is significant, we're still undefeated and that's important.
"We played better than Madrid. We weren't brilliant but we saw a good Barça and they also played well. We can improve."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball