Men’s singles Fish         bt     Simon         6-1, 5-7, 7-6, 6-3Berdych     bt     Querrey         6-7, 6-4, 6-3, 6-2Almagro        bt     Sock         7-6, 6-7, 7-6, 6-1Cilic         bt     Nishikori     6-3, 6-4, 6-7, 6-3Kližan         bt     Chardy         6-4, 6-4, 6-4Women’s singlesIvanovic     bt     Stephens     6-7, 6-4, 6-2Kerber         bt     Govortsova     6-1, 6-2Hlavácková     bt     Kirilenko     5-7, 6-4, 6-4Pironkova     bt     Soler         6-1, 6-7, 6-3Vinci         bt     Cibulková     6-2, 7-5Errani         bt     Puchkova     6-1, 6-1NEW YORK - Top-ranked Roger Federer continued his dynamic U.S. Open form in near-tropical conditions on Saturday while fourth seed Serena Williams braved the steaming heat to avenge a shock defeat she suffered in January.With a potential semi-final showdown with Federer looming, Andy Murray remained in the hunt for his first grand slam crown by defeating Spain’s Feliciano Lopez to reach the fourth round.Women’s second seed Agnieszka Radwanska set up a fourth-round tussle with Italy’s Roberta Vinci by stopping Jelena Jankovic 6-3 7-5 at a steamy Arthur Ashe Stadium."With the hot conditions you really have to fight yourself more than your opponent,” said Pole Radwanska, a sentiment echoed by several players.Federer cruised past Fernando Verdasco 6-3 6-4 6-4 in two hours and two minutes, blasting seven aces and 30 winners against the 25th-seeded Spaniard.Federer has not lost a set at the U.S. Open this year, as he moves closer to a sixth title at the National Tennis Center. Next up is either American Mardy Fish or Frenchman Gilles Simon for a place in the quarter-finals.Verdasco, 28, had 35 unforced errors and 10 double faults as he lost to Federer for the fifth time in as many meetings.Like Federer, Williams has not lost a set but needed a break of serve in the final game of the opening set to grab the momentum as she ousted Russian Ekaterina Makarova 6-4 6-0.Makarova buckled under the pressure of her first-set letdown and was blown away in the second in just 32 minutes.The Russian knocked out Williams in the fourth round of this year’s Australian Open and the American said she was motivated to turn the tables at the year’s final grand slam tournament.Murray, who won Olympic gold last month, recovered from a mid-match lapse to defeat Lopez 7-6 7-6 4-6 7-6 in three hours and 53 minutes. Third seed Murray next plays 15th-seeded Canadian Milos Raonic, who beat American James Blake 6-3 6-0 7-6.