Canberra's Nick Kyrgios won the singles title of the Mayor?s Cup World Super Junior Tennis Championship in Osaka.

Canberra's Nick Kyrgios won the singles title of the Mayor?s Cup World Super Junior Tennis Championship in Osaka. Photo: Getty Images

Canberra's Nick Kyrgios won the singles title of the Mayor's Cup World Super Junior Tennis Championship in Osaka, Japan, on Sunday.

Kyrgios, the tournament's No. 1 seed with a junior world ranking of five, had to beat No. 2 seed Kaichi Uchida, of Japan, to claim the title.

He accounted for the local favourite in a close battle 7-6 (7-5), 7-6 (7-4), the victory ensuring a clean sheet for the 17-year-old, who didn't drop a set all tournament.

His junior world ranking could now rise to as high as No. 3.

It was the first Grade A tournament win for the Daramalan College student, who said it came as a ''huge relief'', having won two junior grand slam doubles titles this year, but no top-level singles titles.

''It was overwhelming, just because there was a lot of expectation. I was just glad to get the job done,'' he said.

The Mayor's Cup is one of 12 annual Grade A tournaments, which award the same number of points as junior grand slam titles, and has an impressive list of recent winners.

In 2003, Marcos Baghdatis defeated Jo Wilfried Tsonga to win it, with Marin Cilic claiming the crown in 2005.

Caroline Wozniacki and Victoria Azarenka took out the girls' title between 2004 and 2006.

Kyrgios paired with Victoria's Omar Jasika to also finish runner-up in the doubles event in Osaka, but there will be no rest for the AIS scholarship holder.

He flew directly to Melbourne yesterday to play in the Bendigo International, the final Australian Pro Tour event for 2012, which starts today.