Cincinnati, OH, USA, 18 August 2015 | AP

Australia’s Bernard Tomic is through to the second round of the ATP Cincinnati Masters with a straight sets win over Sergiy Stakhovsky.

World no.24 Tomic beat the Ukrainian 6-4 6-3 to set up a second round match with qualifier Alexandr Dolgopolov.

The result comes a week after the Queenslander progressed to the third round at the Montreal Masters.

His ranking is currently equal to his career-high mark first set in June.

The early headlines went to Mardy Fish who in his next-to-last tournament of his career upset 20th ranked Viktor Troicki, beating the 20th ranked player 6-2 6-2.

“I was a little surprised at my level,” Fish said. “I hadn’t practised a ton or particularly well for a little while. I was struggling with my serve.

Fish, a wildcard entrant who already announced the US Open will be his last event before retiring, advanced to face second-ranked Andy Murray after his first singles victory on tour in almost two years.

Unseeded Ivo Karlovic also upset 10th-seeded Gilles Simon 6-4 6-7(3) 6-3 while Joao Sousa defeated Philipp Kohlschreiber 6-2 6-7(5) 6-2.