Rory McIlroy has admitted he feels he needs to improve on his game after struggling at this year’s Masters. The Northern-Irishman had gone into the tournament hoping to finally win the prestigious prize at the 16th time of asking. Yet McIlroy never really got going at Augusta this year and finished four over on Sunday. The 34-year-old has now opened up after a difficult time at the tournament – and admitted he has work to do if he’s to finally get the green jacket he craves. “[It’s taught me] I’ve still got a little work to do on my game,” he said. “This is an amazing golf tournament and I am …