Michael Campbell was not even in the world's top 900 only four months ago but he leads the UBS Hong Kong Open at the halfway stage - and does not have world number one Rory McIlroy to worry about in an added bonus.

While New Zealand's former US Open winner shot his lowest round for over six years, a six under par 64, defending champion McIlroy crashed out after four-putting his final green for a 72.

Five days after clinching his European and US Tour money list double with a closing eagle in Singapore, the 23-year-old Northern Irishman played his last seven holes in a shocking six over par to miss by three strokes.

"I feel like I'm hitting the ball pretty good still and I think these couple of days off might actually do me good" - Rory McIlroy 

"I just got on a slide and couldn't stop it," he said. "Obviously not the week that I wanted.

"I was only four off the lead and thinking I could make a couple more and be right back in contention. Unfortunately it just went the other way.

"I didn't putt well last week and sort of got away with it. This week was the same, so I think a bit of putting practice is required in Dubai (The DP World Tour Championship starts there next Thursday).

"I think these couple of days off might actually do me good. It'll give me a chance to rest.

"I think if I was completely fresh I wouldn't have been making the mistakes.

"On the last I saw the projected cut was plus two, so I wanted to try to hole it (for birdie)." His 30-foot attempt caught the lip, but ran on five feet and he took three more.

On nine under Campbell, now 43 and seven years on from his last win, leads by one from Spain's Miguel Angel Jimenez, at 48 trying to become the European Tour's oldest-ever champion, China's Zhang Lian-wei and Swede Fredrik Andersson Hed.

Campbell missed 17 out of 18 cuts in a nightmare nine-month spell, but came third in Portugal five weeks ago and is back up to 339th in the world.

"I'm just happy to be in a position to have a chance," he said. "That's why we play the game. That's why I didn't give up."

He nearly did, though.

"There have been times where I wanted to throw it in. I remember I was back in Sydney (in 2008) said to myself 'Okay, tonight is when I decide whether I'm going to give up the game or keep on playing'.

"I woke up in the morning and there was something inside me that said 'keep on going, you've still got the talent'. It never goes away - it just hides now and then."

Campbell went to the turn in 30, made it four birdies in a row at the 10th and added another on the last.

The tournament is proving to be one for the aged. As well as Campbell and two-time winner Jimenez, the 1,274th-ranked Zhang is 47 and Andersson Hed 40.

With surprise first round leader Javi Colomo falling back after carding a 71, Dane Anders Hansen lies fifth - and he is 42.

Peter Lawrie was the only Irishman to make the cut after recording a second consecutive 68, as Padraig Harrington fell short despite a closing par which included skimming his ball across a lake and back onto dry land. Niall Turner also missed the weekend action after a round of 71 saw him finish on five over, one shot ahead of Harrington.