Rory McIlroy hits his first official shot as world No 1 on the 10th at Doral’s TPC Blue Monster. He signed for a one over 73. Photo Eoin Clarke/ Rory McIlroy confessed that the mental strain of getting to world number one took its toll on him as he crashed to his first over par score for five months in the WGC-Cadillac Championship at a blustery TPC Blue Monster.

Winds gusting over 25 mph spreadeagled the 74-man field and McIlroy could only manage a one over par 73 to finish the day tied for 35th and seven shots behind pace-setters Adam Scott and Jason Dufner.

“To be honest I felt a little flat out there,” McIlroy said after his first over par score since the third round of last October’s Kolon Korea Open. “I shouldn’t, it’s a World Golf Championship, but just felt a little flat.

“Physically, I’m fine.  But mentally, it’s tough.  When you go to Arizona and you’ve got a chance to go to world No. 1; and then Honda, you’ve got a chance to and then, all of a sudden you’re there, and you’re like, well, what do you do.”

McIlroy could see his reign as world number one last just one week - equalling the shortest on record held by Tom Lehman - if Lee Westwood or Luke Donald win this week.

But while Westwood looks unlikely to do that now after a 76, Donald could get there with a top-4 finish. And he was lurking just outside the top 10 after a two under par 70 featuring five birdies, one bogey and a double bogey six.

Having come close to earning the number one ranking with his run to the final of the WGC-Accenture Match Play two weeks ago, McIlroy revealed that he was mentally spent after finally getting there following his sensational victory in the Honda Classic last Sunday.

Playing alongside Westwood and Donald, he went out in one over par with bogeys at the 11th and 18th and a solitary birdie from 11 feet at the par-five 12th.

But he was uninspired on the greens, taking 32 putts as he came home in level with birdies at the par-five first and eighth cancelled out by back to back bogeys at the third and fourth.

“It was a bit of a struggle,” said McIlroy, who narrowly failed to take advantage of a lucky bounce off rocks at the third and then three-putted the fourth. “It was a pretty tricky day but obviously there were good scores out there.  I just didn’t really get anything going.  

“I was trying to sort of play my way back into the round.  I thought if I could shoot under par on the back nine, which was the front nine, post something around 70 or 69, it would have been a good score.”  

“But I made a couple bogeys early on on that nine and couldn’t really get it back. I just need to go out and set myself a target tomorrow and try and post a number.”

Scott and Dufner fired six under par 66’s to lead by two shots from the rejuvenated Dane Thomas Bjorn and Masters champion Charl Schwartzel with seven players including Europeans Alvaro Quiros, Justin Rose and Miguel Angel Jimenez tied for fifth on three under.

Tiger Woods and Phil Mickelson shot level par 72s to share 25th place. But it was a disappointing day for Open champion Darren Clarke and Graeme McDowell, the other two Irishmen in the field.

Darren Clarke tees off on the first at Doral. Photo Eoin Clarke/www.golffile.ieClarke looked likely to lead the Irish challenge when stood on the 18th tee at one under par for the day.

But the 43-year old drove into the lake on the left off the tee and then found water left of the green with his third to rack up a triple bogey seven and sign for a two over 74.

Graeme McDowell, who was sixth here in 2010, failed to make a birdie in a three over par 75.

As for Woods, the 14-time major winner got off to the perfect start when hit a wedge to 22 inches at the 522 yard first and tapped in for an eagle three.

But while he birdied the par-five eighth and 12th holes, he bogeyed the fourth, fifth, ninth and 18th to finish the day six shots off the pace.

“It was just a difficult day,” said Woods, who had 30 putts, three-putting twice. “The wind was blowing putts around, and it made for a very challenging round.”

Donald was the only member of the threeball to birdie their opening hole, the par-five 10th, as McIlroy failed to get up and down from sand short of the green and Westwood  took six by thinning his bunker shot over the green into the lake.

The 38-old from Worksop must win this week to have any chance of getting back to world number one. But he slumped to three over after seven, taking drops from unplayable lies no fewer than three times.

After three-putting the 11th by racing his birdie chance seven feet past, Westwood then zig-zagged his way up the 12th by going from a bush in the right into an unplayable place in bushes on the left before eventually getting up and down from greenside sand for a six.

Men in black. Tiger Woods strides to the first tee. Photo Eoin Clarke/www.golffile.ieAnother shot went for Westwood at the 16th, where he was 70 yards off line in bushes on the left and did well in the end to limit the damage to a bogey five that left him last in the 74-man field on four over.

McIlroy bogeyed the 11th from the middle of the fairway, ballooning his attempted punch to the green and then pitching weakly before missing from six feet.

He while he birdied the 12th from 11 feet after an average chip from the left fringe, it was all a struggle after that as he failed to find much inspiration on the greens.

After chipping dead to save par at the 13th, he bogeyed the 18th, where he was forced to lay up after his drive stopped just a couple of feet short of the lake on the left.

Out in one over par, McIlroy hit a superb 193 yard approach to 15 feet at the par-five first but settled for just a birdie as the eagle putt failed to threaten the hole.

He bogeyed the third but it could have been worse after his second ricocheted off rocks on the edge of the lake but bounced left back onto grass.

However, he failed with a seven footer for par and then three-putted the fourth from 33 feet to go two over before a birdie from five feet at the par-five eighth and a chip and putt par at the short ninth allowed him to escape with a one over 73.

Donald bogeyed the 17th and doubled the 18th after a visit the the lake but came home in two under for a 70 that left him tied 13th.

“Well, obviously Rory has been playing great and Lee has, too,” Donald said. “Both of them played extremely well last week.  But you know, personally, I played pretty solid today, just one little mistake really on 18.  Just a beast of a hole today. 

“I had 227 yards into that and still needed to hit 3‑wood and just pulled it a touch.  But pretty happy with the way I played, five birdies out there, and it was tricky.”

No-one needed to tell Sergio Garcia how tough it was as he signed for a three over 75

The Spaniard had six birdies and a bogey as he raced to the turn in 31. But he collapsed on the back nine, limping home in eight over 44 following a bogey at the 11th and a birdie at the par-five 12th with five successive bogeys from the 13th and a triple bogey seven at the last.