Rory McIlroy of United Kingdom reacts after becoming golf's new world number one player on the 18th green with his win in the Honda Classic PGA golf tournament at PGA National Golf Club in Palm Beach Gardens, March 4, 2012. [Photo/Agencies]

England's Luke Donald surrendered the world No. 1 ranking to Northern Irishman Rory McIlroy yesterday after a poor showing at the US PGA Heritage Classic.

Donald fired a level-par 71 on Sunday to finish on 2-over 286 for 72 holes, sharing 37th place, 16 strokes behind winner Carl Pettersson of Sweden.

Donald needed to share eighth place or better at the Hilton Head Island, South Carolina, event to keep his razor-thin margin ahead of McIlroy in the rankings. He finished six strokes adrift of that mark after matching his highest score in seven Heritage starts.

Once eight players reached the clubhouse ahead of him, Donald was ensured of giving the top spot back to McIlroy, whom he passed last month for the honor.

"Is it a concern? No," Donald said. "I would have liked to have played a bit more consistently this year. I built it up nicely last year through tournaments and winning a bunch.

"As a result there's a little bit of fluctuation in the world rankings now."

Donald, still seeking his first major title, first claimed the top ranking after winning last year's BMW PGA Championship on the European Tour.

Reigning US Open champion McIlroy, who turns 23 on May 4, claimed the top spot for the first time in his young career last month when he won the US PGA Honda Classic, ending a 40-week run by Donald.

But Donald moved past McIlroy two weeks later, reclaiming the top spot by winning the US PGA Transitions Championship.

McIlroy, who was off this week, is not expected to play again until the US PGA Wells Fargo Championship in May at Quail Hollow in Charlotte, North Carolina. Donald will return to PGA play in two weeks at New Orleans starting on April 26.

On the course, Pettersson shot a 2-under 69 to finish the tournament at 14-under, a comfortable five shots clear of former Masters champion Zach Johnson (70).

"The swing felt good," Pettersson told reporters. "I felt calm. It was a great feeling today."

It was his first PGA Tour win since the 2010 Canadian Open and fifth overall that allowed him to match Jesper Parnevik's total for most won by a Swedish player.

Colt Knost's chances of winning his first PGA Tour title vanished with a 74 that put him third, one stroke behind American Johnson. Kevin Stadler (68) and Billy Mayfair (69) tied for fourth at 6 under.