Five-time champion Roger Federer defied 32-degree heat and crushing humidity to reach the US Open last 16 on Saturday as potential semi-final rival Andy Murray almost wilted in the New York sweatshop. Top seed Federer, bidding to be the first six-time winner in 87 years, defeated Spanish 25th seed Fernando Verdasco 6-3, 6-4, 6-4 in a shade over two hours to make the last 16 for the 12th successive year. The Swiss next faces American 23rd seed Mardy Fish, who beat Gilles Simon, the French 16th seed, 6-1, 5-7, 7-6 (7/5), 6-3. Fish prevailed in a match, which finished on Sunday morning despite hitting 74 unforced errors. In stark contrast, third-seeded Murray, the 2008 US Open runner-up to Federer, needed almost four hours to clinch a 7-6 (7/5), 7-6 (7/5), 4-6, 7-6 (7/4) victory over 30th-seeded Spanish left-hander Feliciano Lopez. Olympic champion Murray will next face 15th-seeded Milos Raonic, who defeated American wildcard James Blake and 6-3, 6-0, 7-6 (7/3) on the back of 29 aces to become the first Canadian to make the last 16 in 24 years. Murray, four times a Grand Slam runner-up, had lost only one set in six prior matches against Lopez but had to come back from trailing in all three tie-breakers on Saturday. Federer only faced one break point against Verdasco, a player he has now defeated five times in five meetings. Murray’s 250th career match victory on hard courts, and his seventh in seven meetings with Lopez, came when the Spaniard netted a backhand. Eleventh seed Nicolas Almagro kept Spanish hopes alive when he reached the fourth round for the first time with a 7-6 (7/3), 6-7 (4/7), 7-6 (7/2), 6-1 win over American wildcard Jack Sock. Three-time women’s champion Serena Williams went level with sister Venus on 61 US Open career wins when she coasted into the fourth round. Olympic and Wimbledon champion Williams won eight games in succession to claim a 6-4, 6-0 win over Russia’s world 42 Ekaterina Makarova, the woman who knocked her out of the Australian Open this year. Williams fired 31 winners and eight aces and will next face unseeded Czech Andrea Hlavackova.