CINCINNATI - Novak Djokovic continued his quest for a first title at the Cincinnati Masters while Roger Federer kept alive his bid for a sixth as the seeded pair advanced into the quarter-finals on Thursday. The contrast between the wins could not have been more stark, with top seed Djokovic crushing Belgian qualifier David Goffin 6-2, 6-0 in just 50 minutes.

Federer is seeded fifth and was the winner here a year ago on the fast hardcourt where he thrives. He had to rally from the depths after a disaster of an opening set, finally overhauling German Tommy Haas 1-6, 7-5, 6-3.

The Swiss has gone back to his traditional racquet after experimenting without much success last month with a larger, more modern model. He said he needed to go back to basics to pull off his 12th win from 15 meetings with Haas, seeded 11th. "I wasn't playing great in the first set, I needed to clean up my game from the baseline," said the crowd favourite and fifth seed. "I'm happy to be through to have another match.”

Federer will face off for the 31st time against longtime rival and last week's Montreal champion Rafael Nadal, winner of eight titles from 11 events this season. The Spaniard got a test from Bulgarian Grigor Dimitrov but won 6-2, 5-7, 6-2.

Russian qualifier Dmitry Tursunov upset third seed David Ferrer 6-2, 6-4 as the Spaniard now leaves town with one win from two Masters events over the past fortnight. In other third-round results, Argentine Juan Martin del Potro beat Spain's Feliciano Lopez 6-4, 1-6, 6-4 while American John Isner defeated 12th seed Milos Raonic 7-6 (7/5), 6-4 with the Canadian being treated for shoulder problems.

On the women's side of the dual event, top seed Serena Williams mowed down German Mona Barthel 6-4, 6-1 to move closer to a first title at the tournament.Second seed Victoria Azarenka won a match littered with 13 breaks of serve, defeating Slovak Magdalena Rybarikova 6-3, 6-4.

 Tenth seed Caroline Wozniacki put out Czech seventh seed Petra Kvitova 3-6, 6-2, 6-3.

Giant killer Simona Halep upset Australian 11th seed Samantha Stosur 6-4, 4-6, 6-2, just one day the Romanian stunned Marion Bartoli 3-6, 6-4, 6-1, sending the reigning Wimbledon champ off into an unexpected retirement. Roberta Vinci claimed an Italian showdown with sixth seed Sara Errani 6-4, 6-3 while former number one Jelena Jankovic beat American Sloane Stephens 3-6, 7-5, 7-5.