US Open champion Rory McIlroy has parted company with manager Andrew \"Chubby\" Chandler, it was confirmed on Friday. The 22-year-old world number three -- widely regarded as golf\'s most talented youngster -- has split with Chandler\'s International Sports Management (ISM) firm after a four-year association, an ISM statement said. The surprise move comes after a stellar year for McIlroy which saw the Northern Irish youngster land his first Major. Chandler, who also manages Lee Westwood, Open champion Darren Clarke, Masters winner Charl Schwartzel and Ernie Els, was philosophical about the split. \"Onward and upwards,\" he said in a statement. \"We have had a quite brilliant year. The company is growing and adapting to ensure it stays at the forefront of golf and the business of managing players. We wish Rory every success.\" \"It has been an honour representing Rory and we take great pride in the role ISM has played in guiding him successfully through his formative years as a professional golfer. \"Under our management he has grown into an international figure and he leaves us as a major champion.\" McIlroy has not commented on the split.