London, Jul 11 (IANS): Former Wimbledon champion and member of Novak Djokovic's coaching staff, Goran Ivanisevic, called Nick Kyrgios "a genius" after the Australian stretched his charge to a gruelling four sets in the grass-court major final here on Sunday.

Djokovic produced a tennis master-class to defeat Kyrgios 4-6, 6-3, 6-4, 7-6(3) for his seventh Wimbledon title, and fourth consecutive crown at the grass-court major.

It was Djokovic's 21st Grand Slam title and brought him within one title of Spanish stalwart Rafael Nadal's men's singles record.

Ivanisevic, the 2001 Wimbledon champion, was ecstatic following Djokovic's win.

"For me he was a favourite here. Before the tournament he really played some unbelievable tennis. But you still need to win the tournament, so it was not easy," atptour.com quoted Ivanisevic as saying.

"But (a) Grand Slam is a Grand Slam. He (Novak) has 21. He really deserves it. He really deserves it."

At the same time, the Croatian was highly appreciative of first-time major finalist Kyrgios, who pushed Djokovic to a fourth-set tie-break.

"You cannot prepare (for a) match against Nick Kyrgios. Nick Kyrgios is a genius, tennis genius. He doesn't know what he's going to play next in the point," Ivanisevic said.

"We just concentrate (on) what Novak has to do, the things he has to do, the things he has to be careful (of). When somebody (is) serving like Nick Kyrgios -- for me (he) is the best server in the game by far. Unbelievable tennis player. (He) is very unpredictable."

Kyrgios slammed 30 aces and 62 total winners in the three-hour, one-minute final.

"It's impossible to make tactics. (There are) no tactics," Ivanisevic said. "Fifteen minutes, best returner in the world, he does not touch his serve. You get the chance, then he breaks him."