Tiger Woods withdrew from

Tiger Woods withdrew from

the WGC-Bridgestone Invitational during yesterday's final round, sparking fears that he had suffered further serious damage to his back.

On the day that Rory McIlroy overcame a three-shot overnight deficit to beat Sergio Garcia and reclaim the No.1 ranking from Australia's Adam Scott, Woods'withdrawal casts doubt over his participation in this week's US PGA Championship, the final major of the season.

Playing just his third event since undergoing microdiscectomy surgery in March, Woods was four over par after eight holes when he pulled out on the ninth hole at Firestone Country Club.

The former world No.1 looked in severe pain after hitting his tee shot on the par four, wincing as he struggled to bend down to pick up his tee. Moments later he was on a golf cart being driven straight to the car park where he again looked in real discomfort as he prepared to leave a venue where he has won eight times, including by seven shots last year.

His withdrawal could also have dashed his hopes of persuading Tom Watson, the US Ryder captain, of handing him a wild card for next month's showdown with Europe at Gleneagles should Woods, as now seems likely, fail to garner enough points to qualify for the team as

of right.

Asked if he had suffered the same injury which led to surgery on March 31 and ruled him out of the Masters and US Open,Woods said: "It's just the whole lower back. It happened on the second hole when

I hit my second shot. I fell back into the bunker. Just jarred it. It's been spasming ever since."

On his prospects of playing in the PGA Championship, the 38-year-old added: "I don't know, [I'm] just trying to get out of here."

Woods had made the ideal start to his round with a birdie on the first, but dropped shots on the third and sixth and then ran up a double-bogey on the seventh.

European Ryder Cup captain Paul McGinley, commentating on Sky Sports 4, said: "He looks like he's maybe come back too early. The way he played I saw him hit shots on the front nine there that I've never seen him in his life come close to hitting. There's obviously something going on."

Woods missed the cut in his first event back at the end of June and then suffered his worst ever 72-hole finish in a major championship as a professional, ending up 69th in the Open at Royal Liverpool despite an opening 69.

Watson, meanwhile, continues

to declare that Woods needs to show necessary form and sharpness to have a hope of getting the nod. Time is running out.

"Tiger has got to be honest,

he's got to be very, very honest," suggested Colin Montgomerie,

who will return to the PGA Championship in a playing capacity this week after winning the Senior PGA crown earlier this season.

"If Tiger says to Tom Watson,

'I'm sorry, I don't really feel ready and I haven't come back well enough so please leave me out this time and

I'll be back in 2016', then okay, that's fine. That's an honest statement. Good on you Tiger, go for it.

"But if he does say 'I can help you', then he's got added pressure on him hasn't he? If he doesn't perform [this week], it's a hell of a thing isn't it? Let's hope he does play, I really hope that Tiger plays in the American Ryder Cup team and really gives it 110% because he needed a pick. He's been No.1 I think every other time and then suddenly bingo, he needs a pick. Tom Watson will not be sentimental in any pick.

"He has got to go to Tiger and say 'do you feel that you will help my team get to 14½ points?' If Tiger Woods says yes to that, can you pick three guys ahead of him? Can you honestly pick three guys and leave him out if he says to you he is ready and prepared to give it everything for the cause? I don't think you can.

I think you've got to pick him."

A fortnight after holding off Garcia to win the Open, McIlroy overhauled his Ryder Cup team-mate to claim his first World Golf Championship event.

At Akron yesterday, McIlroy turned a three-shot deficit into a two-shot lead within the space of five holes, before Garcia battled back to leave the pair tied heading into the back nine at Firestone Country Club.

Garcia had played the same back nine in just 27 shots in his second round of 61, but it was McIlroy who came out on top two days later in a tense duel, the 25-year-old carding a closing 66 to finish 15 under par.

After 16 birdies in the first three rounds, Garcia could only manage one in a disappointing closing 71 to finish 13 under, meaning the 34-year-old has now won just three times after holding the 54-hole lead on 16 occasions.

"What I am really proud of this week is following on from the Open with a performance like this," said McIlroy, only the second European winner of the title after Darren Clarke in 2003, told CBS. "I said straight after I did not want any let down, I wanted to keep going and performing until the end of the season.

"It's great to come to one of my favourite tournaments of the year and to perform like this I am pretty satisfied."

McIlroy pulled his opening drive into the rough but had a gap through the trees and hit a superb low pitch to three feet, while Garcia had to settle for a par by two-putting from long range.

Three-time major winner McIlroy then two-putted from long range on the par-five second for another birdie and also birdied the third to take over the lead as Garcia bogeyed, but that did not tell half the story of an amazing hole.

Garcia's errant drive into the crowd somehow knocked the diamond out of a female spectator's engagement ring and after giving her a signed ball, the Spaniard asked for her contact information after hitting his second shot over the green.

Thankfully, the precious stone was quickly recovered but Garcia was unable to get up and down to save par and McIlroy holed from eight feet for a third straight birdie.

When McIlroy also birdied the fifth from five feet it meant a five-shot swing had taken place in the space of five holes and gave the world number two a two-shot lead.

Garcia desperately needed something to go in his favour and it happened on the eighth, McIlroy driving into the rough and finding a greenside bunker with his approach, from where he failed to get up and down.

Garcia then got back on level terms with a birdie from 15 feet on the ninth, McIlroy missing from just six feet.

That meant the pair went into the back nine tied on 14 under par but it was McIlroy who edged back in front with a birdie on the 11th from eight feet, Garcia then missing from a few inches closer.

The decisive moment then came on the par-three 15th, where Garcia's tee-shot left of the green left him with a near-impossible pitch over a bunker and led to a bogey four.

That gave McIlroy a two-shot lead with three to play and when Garcia failed to convert a birdie chance from 10 feet on the 17th his chance had gone.

Low scoring had been the order of the day on the rain-softened course, five-time major winner Phil Mickelson charging through the field with an eight-under-par 62 which featured 10 birdies and two bogeys.

"I don't know what to say, it kind of came out of nowhere," Mickelson said after finishing five under for the tournament. "The first two rounds really threw me for a loop. I have been struggling getting my short irons close and today they were right on.

"I made a lot of birdies and it was nice. Today was a big day to give me a lot of confidence and momentum heading into the US PGA next week."

England's Lee Westwood had also found some welcome form after four consecutive missed cuts, the 41-year-old carding a flawless 63 that did not go unnoticed by watching Ryder Cup captain Paul McGinley.

"If you look at the one pillar that has been consistent throughout the Ryder Cup success we have had since the 90s it has been Lee Westwood but you want to see Lee in form," said McGinley on Sky Sports 4, well aware that Westwood is outside the automatic qualifying places.

"He is not going to get in on his reputation alone. He needs some form, he knows that and it's good to see him playing well today."