second seed simona halep was given a tough workout but managed to battle past qualifier, kateryna kozlovabreaks each in the first set, and in the ensuing tie—break the romanian world number two came out on top. kozlova provided halep with a tough test, but fatigue seemed to be catching up with her as the romanian broke in the 12th game of the second to win the match with backhand down the line. serena williams' return to tennis after a five—week break ended with her retiring from her match against garbine muguruza because of a viral illness. she was playing her first tournament since the australian open in late january, when she lost in the quarterfinals. she said in a statement: "before the match, i did not feel great, and then itjust got worse with every second: extreme dizziness and extreme fatigue." 0pen champion francesco molinari sank a as—foot birdie putt to come from five shots behind on sunday and win the arnold palmer invitational. it gave him a two—shot lead at 12—under and no one got closer than two shots the rest of the way. he won for the fourth time in the last nine months.