The midfielder was delighted with his team-mate’s two-goal comeback against Getafe and looked ahead to the top-of-the-table clash against Atletico
The Argentine star returned from two months out of action with a hamstring injury to come off the substitutes' bench and score twice at Camp Nou in a 4-0 first-leg victory.
Ahead of Monday's Ballon d'Or gala, Xavi suggested the forward’s 26-minute comeback cameo was a timely reminder of his quality and the perfect answer to anyone who was beginning to doubt him.
"Even after being out for so long, what Messi did was not a surprise to us," the 33-year-old told reporters after receiving a Fair Play award from the association of former Barcelona players.
"Leo returned to prove he is still the number one - the best player in the world. He is extremely hungry and motivated to perform now that he is back.
"I think these two months out have served him well. The team need him and he will continue to show how important he is with every match."
Xavi also discussed Saturday’s massive Liga clash against Atletico Madrid at the Vicente Calderon, which gives both sides - currently level on 49 points from 18 games - an opportunity to open up a lead at the top.
The Spain international acknowledged the importance of the contest but insisted nothing would be decided by the end of the match, even if it represented a chance to make an important statement.
He continued: "It is a game that is vital but not definitive. We could certainly strike an important blow and make a big impact on the table.
"We need to try and be the protagonists and it is good that we reach this game in a great spell of form.
"But it will be a difficult and complicated game. They are playing at home and they are very compact defensively."