World No 1 Roger Federer defeated Aussie No 1 Bernard Tomic with 6-2, 6-4 scoreline to reach the quarter-finals of Cincinnati Masters on Thursday.

Federer next faces American Mardy Fish, a 6-3, 6-3 winner over Czech Radek Stepanek.

"That was the monkey jumping off my back," said Fish, who scored his first win in five meetings against Stepanek. "He's been a very tough opponent for me over the years. Not only has he beaten me, he's beaten me pretty soundly most of the time. I certainly felt good. I feel fresh and strong. This summer has gone well for me as far as getting my match fitness back. I have had a lot of great wins on that court here and played a lot of great matches."

Second seeded Serbian Novak Djokovic advanced into the quarters when his opponent Russian Nikolay Davydenko retired midway because of an injury after suffering a bagel in the first set.

French lucky loser Jeremy Chardy posted the upset of the day as he upset defending champion Andy Murray 6-4, 6-4.

Chardy next faces sixth seeded Argentine Juan Martin del Potro, who battled past Serbia’s Viktor Troicki 7-6(2), 2-6, 6-1.