Rory McIlroy was furious to be slapped with a two-stroke penalty for not taking full relief from a spectator walkway in the third round of the Abu Dhabi HSBC Championship.

"Foot fault," wrote the fiancé of tennis star Caroline Wozniacki on Twitter, though he was far from a happy camper afterwards after being penalised under Rule 25-1.

Instead of going into the final round just a stroke behind leader Craig Lee, he will start tied for fourth place and three adrift on nine under after his 68 turned into a 70 when playing partner Ricardo Gonzalez's veteran caddie Dave Renwick informed him on the 18th that he may have played from the wrong place on the second hole.

"I hit my second shot on the second hole onto the spectator crosswalk, so I took a drop out of it, which obviously you are allowed to do.," McIlroy told Sky Sports after a review and visit to the scene of the 'crime' ended up with him being penalised two shots, turning his par five into a double bogey seven.  

"I played my shot but I didn't notice that my left foot was still on the white line and you need to take full relief. I didn't even know my foot was on the line.

"We went out there to see where my divot twas and it was clear that I couldn't have played the shot with my feet anywhere else. I guess I was just so much into the shot that I didn't even realise.

"It was unfortunate but that's the rules of this game. 

"[David Renwick] said to me on 18, 'I think you need to call a rules official because I think you were standing on the line or inside the line on the second hole.' [I said] 'Okay, yeah no problem, I don't want to sign an incorrect score card.'

"So we got the rules guys to come but they couldn't see anything on video. But we went out there and check the divot from where I hit the shot and it was clear that my foot had to be on the line to play the shot." 

Asked how sickening this felt in the light of the fact that he had been penalised in Abu Dhabi for illegally brushing away some sand between his ball and flag on the ninth hole in 2012, costing him two shots and the halfway lead, he said: "If anything it was a disadvantage [today] because I dropped it in a bad lie and didn't make birdie. I hit it to 15 feet and two putted. 

"The thing is, if I had realised or if I had known that my foot was on the line, I would have said, 'hold on a minute here, I need to take full relief. It's a bad lie anyway, drop it again I might get a better one'.

"It's disappointing, I don't think I gained any sort of advantage by my foot being on a bit of white paint."

Asked if his caddie JP Fitzgerald was unaware of the rule or simply couldn't see his foot, McIlroy said: "He didn't see the foot.

"He was just focussed on my playing the shot, the same as I was. I guess when you are standing over a shot, you don't realise where your feet are. You are just looking at the ball and trying to execute as best you can. 

"I guess I just have to make up those [two] shots as early as possible tomorrow and get off to a fast start. I felt like I hung in there well and had a lot of opportunities on the back nine that I didn't take. It was nice to birdie 18 but it was all sort of in vain so I need to go out there and get off to a good start tomorrow."

Having finished 11th in Abu Dhabi in 2008, tied fifth in 2009, third in 2010 and runner up in 2011 and 2012, McIlroy is now more motivated than ever to finally win in Abu Dhabi

"I'd like to think so," he said. "I think it gives me a bit of extra motivation. Not that winning this tournament was not motivation enough. Stuff like this is sort of stupid. There are a lot of stupid rules in golf."

McIlroy was clearly upset by the incident with The National's Steve Elling tweeting: "As Rory walked onto stage in media center to explain ruling, he slammed a wedge he had in his hand on the wooden platform in anger."

Lee shot a 69 to lead by two strokes on 12 under par from India's Gaganjeet Bhullar (66) and Open champion Phil Mickelson, who stormed up the leaderboard thanks to a nine under par 63.

Michael Hoey is tied for sixth, four off the pace on eight under after a 68 with Paul McGinley (72) tied 25th on four under.

Darren Clarke's 72 left him joint 46th on one under with Damien McGrane joint 60th on one over after a 75 and Gareth Maybin joint last on three over after a 76