Luke Donald held off the challenge of Paul Lawrie and Justin Rose to retain the BMW PGA Championship and return as world No.1 in emphatic style at Wentworth.

The Englishman, who led fellow-countryman Rose by two shots going into Sunday's final round, shot a birdie laden four-under 68, to finish 15-under for the tournament, four shots clear his playing partner and Scot Lawrie.

The former Open champion enjoyed the round of the day, a 66, to join Rose tied for second place after a fourth round of 70 from the 31-year-old.

Luke Donald
Donald won by four shots from Lawrie and Rose.

While the performance of Lawrie and Rose will have enhanced their hopes of qualifying for Jose Maria-Olathabal's Ryder Cup team, the week belonged to Donald, who regains the world No.1 spot for the first time since March.

The absence of Rory McIlroy, who missed the cut for the European Tour's prestige event, meant a top nine finish for Donald would ensure he usurped the US Open champion at the top.

And the enormity of the occasion looked to be getting to the defending champion early on Sunday, as Rose drew level at 10-under with consecutive birdies at three and four, as Donald made a six at the par five fourth.

However, it was parity that Rose held for just two holes, as Donald surged back into the lead with back-to-back birdies of his own at six and seven.

Heading into the back nine, Donald landed a massive blow, going three ahead with a superb 15-footer at the 10th.

Rose's birdie opportunities were coming thick and fast, but his failure to capitalise meant the South African-born player began chasing pins, leading to his demise at 16, shooting a five as Donald went four ahead.

It was a lead he refused to relinquish, and as Lawrie finished with successive fours at 17 and 18, Rose was forced to share second place, as Donald cruised to victory to become just the third player, after Nick Faldo and Colin Montgomerie, to make a successful defence of the PGA Championship.