Defending champion Viktor Troicki retained his Sydney International crown after edging an evenly-matched contest with Grigor Dimitrov on a final-set tie-break.

World number 22 Troicki cantered to the title last year, seeing off Mikhail Kukushkin in straight sets, but he was forced to do it the hard way against Dimitrov on Saturday.

The Bulgarian, without an ATP title since June 2014, romped to the opening set but could not replicate that form in the second as Troicki forced a decider in equally emphatic fashion.

With no quarter given by either man in the final set, it went to a tie-break and having saved match point, Troicki converted his second opportunity to seal a 2-6 6-1 7-6 (9-7) triumph.

A successful defence looked a long way off when Dimitrov began the first set with a bang, breaking in the opening game before repeating the feat in game seven as he got his nose in front.

But Troicki responded strongly, and three breaks in set two saw him level the match with a minimum of fuss.

A break in game nine of the decider saw Troicki serving for the title, but Dimitrov showed his fighting spirit to hit back immediately and set up a tie-breaker.

Having wasted a match point at 6-5, Troicki then saved one at 6-7 before eventually securing victory and a fifth ATP crown.