The draw sees Real now just four points ahead of Barcelona on the table.
"We expected to take three points tonight, mainly because we played at our stadium, but there's nothing we can do about it now. Every point is essential and we must focus on Wednesday's match against Atletico Madrid," said Xabi.
"We have the lead and, regardless of how large it used to be, we must move on. We'll have to play two league games before our first match against Bayern Munchen."