Andy Murray wrong to split with Ivan Lendl - Goran Ivanisevic

Andy Murray won the US Open, Wimbledon and Olympic gold with Ivan Lendl as his coach

Andy Murray made a mistake splitting from coach Ivan Lendl, former Wimbledon champion Goran Ivanisevic says.

Murray takes on Portugal's Joao Sousa in the Australian Open third round at approximately 04:00 GMT on Friday.

The Briton is now coached by Amelie Mauresmo after ending his partnership with Lendl in March last year.

"Last year was up and down for him, he changed the coaches. For me that's maybe his biggest mistake, letting Ivan go," Ivanisevic told BBC Sport.

"Because it was a perfect match. They did everything well together.

"They won two Grand Slams, he played the best tennis under Ivan, they were similar tennis players."

Murray, 27, won the US Open, Wimbledon and Olympic gold under Lendl, but they went their separate ways after a little over two years together when the Czech-born American could not commit to enough weeks on tour.

After Lendl and Murray split up, former women's world number one Mauresmo began working with the Briton

Murray began working with Mauresmo in June and and picked up three ATP titles at the end of a season in which he returned from back surgery.

The Scot has not reached a Grand Slam final since beating Novak Djokovic at Wimbledon two years ago, although Murray is optimistic he is now back to his best.

Ivanisevic, who coaches US Open champion Marin Cilic, believes Murray will add to his two major titles.

"Andy is a great tennis player, a great competitor, he's going to be back and he's going to win more Grand Slams. If not this year, next year," said the Croat, who won Wimbledon in 2001.

"He can easily win a Grand Slam this year. What he played last year was way off the standard of Andy Murray.

Murray took one hour 42 minutes to beat Marinko Matosevic to reach the last 32 for the seventh year in a row

"There was some brilliance but overall it was medium."

Murray has made a solid start to his Australian Open campaign with straight-sets wins over India's Yuki Bhambri and Australian Marinko Matosevic, and he holds a 3-0 record against Sousa.

"He fights hard, he has a great attitude," Murray said. "He doesn't have one massive weapon, but he definitely gets the most out of his game. He's physically in very good shape. He lasts the long matches well. He'll make it tough for me."

Sousa is ranked 55 in the world and believes he will pose a much greater threat than in 2013 when Murray beat him 6-2 6-2 6-4 in the Australian Open second round.

"I've got a lot of experience, I think I'm another player now," the 25-year-old from Guimaraes said.

"I think the major difference is that I have more experience of the circuit. The other time I played him here it was my first time in a big stadium against a great player.

"Now I have played a lot of times with great players. For sure, that counts."