( CNN ) -- Andy Murray started the 2014 season off slowly , which might have been predicted given he had back surgery last fall . He picked up his game at the French Open only to suffer a bewildering loss to Grigor Dimitrov at Wimbledon as the defending champion . Things almost got worse for Murray on the opening day of the U.S. Open , as he suffered from cramps throughout his body before seeing off Dutchman Robin Haase 6-3 7-6 1-6 7-5 on Monday . Despite Murray being in distress , Haase could n't serve out the fourth set and also squandered a break chance in the final game when he netted a fairly routine forehand volley . For much of the last two sets , Murray struggled with his movement , did n't get pace on his serve and clutched at his body . Haase was `` incapable of taking his opportunity , '' Boris Becker , the coach of world No . 1 Novak Djokovic who was analyzing the match for Sky Sports , said . `` Murray was presented to Haase on a silver platter in that fourth set but Robin did n't like it . '' Murray , known for his endurance , said he began to cramp after an hour and 45 minutes . That was n't `` normal , '' he added . `` And then I did n't really know what to do in that third set , because my quads were cramping and then I started to get it in my lats so when I was throwing the ball up to serve , and then in my forearms , '' Murray told Sky . `` I did n't know whether to conserve energy or to try and finish it in three sets , but then I got broken at the beginning of the set . I just tried to hang around . I was trying to play without using my legs much . '' Murray -- taken to five sets by Haase in New York in 2011 -- was also left wondering why his body let him down . `` I need to work out why that happened today because it should n't happen after an hour and 45 minutes regardless of the temperature , '' he said . `` It was hot but it was n't particularly humid and we did n't play loads of long rallies in the first couple of sets , either . '' If it was only down to cramps , Murray could very well make a complete recovery and the 2012 champion caught a break in the draw because his next opponent is Matthias Bachinger , not tricky Czech Radek Stepanek . Bachinger upset Stepanek in straight sets . In the women 's draw , second-seed and French Open finalist Simona Halep survived a scare , too , eventually overcoming inexperienced American Danielle Rose Collins 6-7 6-1 6-2 . There were victories for fourth-seed Agnieszka Radwanska , sixth-seed Angelique Kerber and 19th-seed Venus Williams . Williams , 34 , beat the nearly 44-year-old Kimiko Date-Krumm 2-6 6-3 6-3 .
Andy Murray begins his U.S. Open by toiling past Robin Haase in four sets . 2012 champion Murray is hoping to find his form after slumping since July . Women 's second-seed Simona Halep rallies to beat a young American . Agnieszka Radwanska , Angelique Kerber and Venus Williams also through .