Updated

Akron, OH (SportsNetwork.com) - Rory McIlroy birdied four of the first five holes on Sunday to grab the lead, and he went on to win the WGC-Bridgestone Invitational by two strokes.

McIlroy, who won his last start at the Open Championship, closed with his second straight 4-under 66 to end at 15-under-par 265. The win will move McIlroy back to the No. 1 spot in the world rankings on Monday.

"What I am really proud of this week, was following up the Open Championship with a performance like this. I said straight afterward, I didn't want any letdown. I wanted to just keep going and keep performing well to the end of the season," McIlroy said. "It's great to come to one of my favorite tournaments of the year, it really is. I love the course here in Akron, and to perform like this, I'm pretty satisfied."

Third-round leader Sergio Garcia was unable to get anything going in the final round. He carded a 1-over 71 and ended alone in second place at minus-13 at Firestone Country Club.

Marc Leishman shot 3-under 67 and ended in third at 12-under 268. Justin Rose (69), Charl Schwartzel (64), 2012 winner Keegan Bradley (69) and Patrick Reed (65) shared fourth place at minus-9.

Adam Scott, the 2011 champion, bogeyed three in a row on the back nine to fall out of the top five. He managed a 1-over 71, which left him tied for eighth at 7-under-par 273. By finishing outside the top five, Scott will lose his spot atop the world golf rankings on Monday.

The 2013 Masters champion was joined at minus-7 by Graeme McDowell (66), Ryan Moore (67) and Rickie Fowler (67).

Before the leaders teed off, the big story was Tiger Woods and his withdrawal from the tournament. Woods injured his back on the second hole, but made it to No. 9. After his tee shot on the par-4, Woods gingerly walked down the fairway before pulling out.

"It happened on the second shot. I just jarred it and it has been spasming since," Woods told a tour official as he left the parking lot.

McIlroy, who also held off Garcia at Hoylake en route to winning the Open Championship, got off to a fast start as he stuffed his approach at the first to three feet. After he kicked that in for birdie, McIlroy 2-putted for birdie on the par-5 second to get within one of Garcia, who parred one and two.

The par-4 third proved to be the turning point. Garcia found the left rough off the tee, and his second sailed into the right rough. He chipped to six feet, but missed his par effort. The bogey dropped Garcia to 13-under.

Meanwhile, McIlroy dropped his second shot inside 10 feet and drained the birdie putt. With the 2-shot swing, McIlroy was now one clear of his playing partner.

"That's what I wanted to do. I played the first few holes really well this week anyway. It really started last night," admitted McIlroy. "Making birdie on those final two holes after the rain delay and then coming out today and birdieing the first three holes, playing that five-hole stretch in 5-under par really set me up to have a great chance to win this golf tournament."

McIlroy moved to 15-under with a 7-foot birdie putt on No. 5. He was two clear at that point, but trouble loomed. McIlroy dumped his second shot in a greenside bunker at the eighth.

The Ulsterman blasted to 11 feet and 2-putted for bogey. Garcia rolled in a 15-footer for birdie on the ninth to forge at tie for the lead at minus-14.

McIlroy answered with an 8-foot birdie putt on No. 11 to regain the lead. Garcia missed the green at the par-4 15th, and had a tough lie just above a sand trap.

Garcia blasted his chip shot 34 feet behind the hole. He 2-putted for bogey to fall two behind.

McIlroy cruised home from there. He 2-putted for par on the final seven holes to seal the win.

Garcia had chances down the stretch to putt pressure on McIlroy, but failed to convert. The Spaniard missed birdie putts of 20, 8 and 21 feet on the final three holes.

"I didn't feel comfortable on the greens at all. With the speed of the greens changing quite dramatically after the rain, they were quite slow," said Garcia. "I just couldn't get it and I was second-guessing myself on every putt."

NOTES: McIlroy earned $1.53 million for the win ... This was his eighth win on both the PGA Tour and European Tour ... McIlroy had been the last player to win back-to-back starts, which he did at the 2012 Deutsche Bank Championship and BMW Championship ... Woods was the last player to win consecutive starts heading into the PGA Championship. Woods did so in 2009, but that was also the year Y.E. Yang beat Woods at the PGA ... There was an hour, 15-minute delay earlier in the day due to heavy rain ... The top players on the PGA and European Tours will be in Lexington, Kentucky, next week for the PGA Championship, where Jason Dufner will defend his title.