By Pritha Sarkar

LONDON (Reuters) - Nick Kyrgios described his first-round clash with the oldest man at Wimbledon -- wily Czech Radek Stepanek -- as "pretty crazy" on Saturday, saying the 37-year-old had been offering to help coach him.

Stepanek likes nothing better than to make life difficult for more celebrated opponents, as world number two Andy Murray discovered last month when he came within two points of defeat in the first round of the French Open.

But Stepanek, the oldest man in the singles, may end up regretting offering the Australian tips on how to win matches when the two face off on Tuesday.

"To play Stepanek obviously is pretty tough. I'm really good mates with him as well," 21-year-old Kyrgios, who has been bumped up from his world ranking of 18 to 15th seed, told reporters.

"He was just helping me a little bit. So ... playing him now, it's pretty crazy."

Asked what kind of pointers he had been given by Stepanek, who coincidentally was the first player the Australian faced when he made his grand slam debut at the French Open in 2013, Kyrgios swiftly changed the subject.

"He was offering to help me a little bit. He's getting towards the end of his career," he said. "He's still playing some great tennis. I feel like grass is his best surface. 

"I know it's going to be very tough," added Kyrgios, who could meet 2013 Wimbledon champion Murray in the fourth round.

"For me, they're just fun matches. I'm not looking too far ahead. I know the Kyrgios‑Murray fourth round is pretty exciting, but I've got some tough matches ahead."

Kyrgios reached the Wimbledon quarter-finals in 2014, but made the wrong sort of headlines last year when he was accused of 'tanking' (not trying) during some points of his defeat by Frenchman Richard Gasquet.

He was fined and given a suspended ban weeks later for making lewd remarks about the girlfriend of Stanislas Wawrinka during a match between the pair in Montreal.

Asked if he had been warned of his behavior coming into the Wimbledon, he snapped: "No, I just compete."

(Reporting by Pritha Sarkar, editing by Martyn Herman)