Current world No. 1 Novak Djokovic, former round victories Wednesday at the $2.43 million Western & Southern Open, an ATP Masters and U.S. Open Series event.

The 2008 and 2009 Cincinnati runner-up Djokovic defeated burgeoning young American Ryan Harrison 6-2, 6-3. The Serb bested Mardy Fish in last week's Masters finale in Montreal.

Djokovic is an amazing 54-1 this season, including titles at Wimbledon and the Australian Open, and he's already captured five Masters championships this year.

The second-seeded Nadal handled French qualifier Julien Benneteau 6-4, 7-5, while a fourth-seeded Murray mauled oft-injured former top-five star David Nalbandian of Argentina 6-4, 6-1 on the hardcourts at the Lindner Family Tennis Center. Nadal and Murray were a pair of shocking early losers last week in Montreal.

Murray captured this Masters tournament back in 2008, while Nadal is the all- time Masters titles leader with 19.

Meanwhile, fifth-seeded Spaniard David Ferrer came back to top promising Bulgarian wild card Grigor Dimitrov 4-6, 6-1, 7-5, sixth-seeded Frenchman Gael Monfils stopped Croat Ivan Dodig 4-6, 6-3, 4-0, retired, and seventh-seeded American Mardy Fish popped nine aces and leveled former top-five Russian Nikolay Davydenko 6-0, 6-2 in 62 minutes. Fish was last week's Masters runner- up to Novak Djokovic in Montreal and lost to Swiss icon Roger Federer in last year's finale here in Cincinnati.

Next up for Fish will be sweet-swinging Frenchman Richard Gasquet.

Ninth-seeded Spaniard Nicolas Almagro held off 6-foot-10 Croat Ivo Karlovic 6-3, 5-7, 7-6 (7-2) to reach the round of 16, while 10th-seeded Frenchman Gilles Simon overcame Janko Tipsarevic 6-7 (3-7), 6-2, 6-3. A 12th-seeded Gasquet got past tall South African Kevin Anderson 7-6 (7-4), 6-4, and American qualifier Alex Bogomolov Jr. stunned 15th-seeded Wimbledon semifinalist Jo-Wilfried Tsonga of France 6-3, 6-4. Bogomolov Jr. will meet the Aussie Open runner-up Murray on Thursday.

Additional second-round wins came for Czech qualifier Radek Stepanek, Spaniard Fernando Verdasco and German Philipp Kohlschreiber. Stepanek, a surprise titlist in Washington, D.C. two weeks ago, defeated Kazakhstan's Andrey Golubev 6-3, 7-6 (7-2) on Day 4. The former top-10 Verdasco will tangle with his countryman and fellow left-hander Nadal on Thursday.

This week's winner will collect $496,000.