Kyrgios tips De Minaur to give Rafa a scare

LONDON, July 5 (Reuters) - Nick Kyrgios fired a warning to Rafael Nadal after continuing to lead a strong Australian challenge at Wimbledon on Thursday.

The 23-year-old maverick kept himself under control during an impressive straight sets defeat of Dutchman Robin Haase and is a potential semi-final foe for Nadal.

But it is another young Australian, 19-year-old Alex De Minaur, who Kyrgios is predicting could cause Nadal problems.

De Minaur plays the Spaniard in the third round after beating Frenchman Pierre-Hugues Herbert.

"It's awesome. He's going to be a guy that's going to love playing on grass for his whole career," Kyrgios told reporters.

"These type of balls, nightmare, so flat. He's a great returner. I honestly think he can cause some damage the next round. I don't think Rafa is going to be liking the ball that's going to come at him constantly for three hours.

"It's going to be a tough ask for him, but I think he could definitely cause a little bit of discomfort."

With 30-year-old Matthew Ebden also into the third round in the bottom half there is plenty for Australian fans to cheer, although the focus is very much on Kyrgios, who himself stunned Nadal at Wimbledon four years ago.

Kyrgios, seeded 15, arrived at Wimbledon in good form after strong runs on the grass in Stuttgart and at Queen's Club.

And he followed a first-round win over Denis Istomin with another focussed display on Thursday to set up a clash with Japan's Kei Nishikori who he is yet to beat and who he described as a 'nightmare' to play.

"The first two sets, I was pretty impressed with my performance," Kyrgios said of his 6-3 6-4 7-6 defeat of Haase.

"Third set got a bit rocky. I was getting a bit out of control. I was losing my focus. I was concentrating on things that were so irrelevant.

"When I found the composure again, I got on with things, was able to close out the match."

No Kyrgios match could pass off completely peacefully though and he twice got into dispute with umpire James Keothavong -- once over a foot fault being called and on another occasion when a line judge reported him for swearing.

"It's not his job to rat on me," Kyrgios told the umpire.

Kyrgios is one of the players being tipped as a potential champion here but said it was still too early to get excited about anyone else than the usual suspects.

"Murray not playing helps," he said. "I mean the other three guys are I think still playing really good. Novak (Djokovic) is looking really confident. Rafa beat a tough guy today on grass.

"Federer is just dicing people up. I don't know if we can do much. We can just take care of business every day until we meet them. Hopefully we can play our best tennis." (Reporting by Martyn Herman; Editing by Hugh Lawson)