Mata: Bale the ultimate game-breaker
Rafa Benitez's men take on Spurs tomorrow in what Mata has described as a cup final, as both teams challenge for Champions League qualification.
Chelsea are in pole position - currently three points ahead of Tottenham - but a victory for Andre Villas-Boas' men would mean three London clubs - Spurs, Chelsea and Arsenal - are all within a point of each other with two games to go.
If Chelsea are to beat their London rivals at Stamford Bridge tomorrow, they will have to negate the threat of Bale - the player of the year and Tottenham's main attacking threat.
Mata said: "For me, Gareth is, right now, one of the best in the world. Not just in England, not just in Europe - in the world.
"He is able to decide a game as he did on Saturday (against Southampton). He has the pace, he has the quality, he is strong, he is very young.
"So he is very good right now, and he has a bright future for sure."
Villas-Boas has also hailed the impact Bale is making this season, especially in the free role granted to him.
"He has been outstanding this season," said Villas-Boas. "He has enjoyed his performances and that is vital for any football player.
"Managers have to guard against limiting them through too much organisation, but that hasn't been the case with Gareth who has played in a different position to the one he has played in before.
"Doing that has given him the chance to score more goals which has contributed to his wonderful season, plus he has the ambition to be at the very top.
"The central role we have played him in was was born out of an experiment in Baltimore, America, when we played Liverpool in a pre-season game.
"Fortunately it is something that worked for us and due to a couple of injuries it was something that we had to keep trying.
"We fine-tuned Gareth to play there and he has been tremendous because his talent allows him to be adaptable.
"I'm not sure that the shift is definitive but it does give us the option of using him in different positions. At the moment, though, the goals he is getting are giving him the buzz to play there."