Dubai: US Open champion Rory McIlroy's 'slim hopes' of overhauling world number one Luke Donald and capturing the European Tour season-ending Race to Dubai title are being hampered by a long-standing virus.   

The Northern Irishman, who won the Hong Kong Open on Sunday to keep alive his bid to topple money list leader Donald, attended a Dubai hospital on Monday for tests on the stomach bug he picked up at the end of October while competing in China.   

"I won't get the results back until later on this week," he told reporters on Tuesday. "I picked up a virus and my white blood cell count was very low, so the tests were to see if it's back up again."   

McIlroy will claim the European Money list for the first time if he wins this week's $7.5 million Dubai World Championship and Donald finishes in a tie for ninth with at least two players, but the illness is hampering his preparations.   

"I'm not energy-wise where I want to be, but I took a day off yesterday and took it easy. I'm going to play the pro-am today and practise and I'll probably take another day off tomorrow, maybe hit a few balls," McIlroy said.   

After finishing in a tie for fourth in the WGC-HSBC Champions event in Shanghai last month, McIlroy went holidaying with his girlfriend, world number one tennis player Caroline Wozniacki, in the Maldives and then Dubai.   

However, McIlroy was feeling so unwell in the Maldives he visited a hospital on three separate occasions to be put on an intravenous drip.   

Got To Win

He put that to one side though to claim victory in Hong Kong with a dramatic finish, holing out from a greenside bunker to claim a two-shot victory over Gregory Havret of France.   

The victory proved that despite feeling unwell, McIlroy remains as capable as anyone to take first prize in Dubai although he does not believe that it will be enough to claim the money list title.   

Donald holds a lead of more than $1 million over McIlroy, making the Englishman a strong favourite to become the first player to win the order of merit titles on both sides of the Atlantic after claiming the U.S. PGA version in October.   

"I've got to win and Luke has to finish outside the top nine or 10, whatever it is. I'm really not counting on him to do that because he's only finished outside the top-10 about twice this year," McIlroy said of his Ryder Cup team mate.   

"Luke has been very, very consistent and he's always had a good short game, and he always holes the putts that he should but one of the big reasons that he's done so well this year is that his driving has improved.    

"He's never been the longest off the tee, but he's starting to hit the fall more in the fairway, and set himself up well with great an great iron game, and that gives him plenty of chances for birdies."   

However, always the optimist, McIlroy was glad the race was still on.   

"It's a golf course that I've had some success on the last couple of years with a third place and a fifth place.   

"So I am excited to be here and there's still a lot to play for. I've still got a slim chance of trying to win the Race to Dubai, and it's so nice to just have that coming here this week."