(REUTERS) - Nick Kyrgios shelved the on-court histrionics and let his tennis do the talking to win an enthralling battle against rising Belgian David Goffin 4-6, 6-3, 7-5 and clinch the Japan Open on Sunday.

The Australian No. 1, long criticised for his temper tantrums, was a model of composure as he overhauled the world No. 14 for the biggest title of his career and his third overall.

"It was a great week and I'll be here again," 21-year-old Kyrgios said at the trophy ceremony, thanking the crowds for their support and tournament organisers for the "amazing" food.

"I'm going to come here, for sure, for my whole career."

Since bowing out of the US Open with a hip injury in the third round, a retirement that prompted American great and TV pundit John McEnroe to question his commitment, Kyrgios has shown tantalising signs of realising the potential that his gifts have long promised.

The world No. 15 returned home to help Australia retain their place in the Davis Cup World Group with victory over Slovakia in their Sydney play-off and his triumph in Japan featured an impressive semi-final win over world No. 8 Gael Monfils.

Goffin, a highly-fancied 25-year-old, was the first to take a set off Kyrgios in the whole week at Tokyo and was successful in blunting the Australian's monster serve early with a crisp returning game.

But the Australian gradually turned the tide, wearing down the fleet-footed Goffin with a succession of thumping forehand winners.

Both blew a pile of break points, with Kyrgios converting two of his 13 chances, only marginally better than Goffin's one from 12.

But in a game of fine margins, it was enough for the Australian, who landed the decisive blow at 5-5 in the third set and calmly served out the match.

Kyrgios picked up the US$310,000 (S$425,700) winners' cheque and a shot of confidence in time for this week's Shanghai Masters.