KEY BISCAYNE, Fla. (AP) ? Sam Querrey won in his first match as the top-ranked American, rallying past Lukasz Kubot 4-6, 6-3, 6-3 Saturday at the Sony Open.
The 20th-ranked Querrey moved ahead of No. 23 John Isner this week. Querrey lost his first service game but held the rest of the way and hit 12 aces against Kubot.
On a sunny, humid afternoon, 2009 champion Andy Murray needed only 56 minutes to beat Bernard Tomic 6-3, 6-1. Murray is seeded No. 2, and Tomic fell to 2-15 against top-10 opponents.
No. 6-seeded Jo-Wilfried Tsonga beat Viktor Troicki 7-6 (6), 6-3. No. 8 Richard Gasquet defeated qualifier Olivier Rochus 7-5, 6-2.
No. 18 Philipp Kohlschreiber lost to David Goffin 7-6 (5), 4-6, 6-2.
In women's play, defending champion Agnieszka Radwanska, seeded fourth, lost serve seven times and needed nearly 2? hours to beat Magdalena Rybarikova 7-6 (5), 2-6, 6-3. No. 9 Caroline Wozniacki lost to wild card Garbine Muguruza of Spain, 6-2, 6-4.
No. 5 Li Na beat No. 25 Varvara Lepchenko of the United States 6-2, 6-4. Seeded players had their opening matches after receiving first-round byes.
The 25-year-old Querrey said being the top-ranked American has provided only a modest boost in confidence.
"Some days more than others," he said. "I never thought about it out there today. Haven't really thought about it much. Felt like another day out there to me. Nothing new."
Querrey won despite a lack of rest. He's staying near downtown Miami, site of a weekend electronic music festival.
"I'm not sleeping well because of this Ultra Festival going on," he said. "I could hear the bass, and strobe lights were shining in my hotel, so it's hard to sleep."