England's Tom Lewis was a further shot behind in third after a round of 65.

American Johnson, who headed into the final round in a share of the lead with Li, finished with back-to-back birdies to claim victory at 19 under par.

"I am pleased with the outcome, but feel I should have played a lot better," said Johnson, who will move to second in the world rankings on Monday.

"I am pleased to get back to number two and hope there is more to come in the next few weeks."

Li also claimed a shot back at the 18th to edge ahead of Lewis, who had started the day with five successive birdies.

A four-under-par final round made Ian Poulter the next best-placed Englishman in a tie for sixth place at 11 under par, while compatriot Ross Fisher and Wales' Bradley Dredge finished on nine under.

Saturday's third round had been dominated by the disqualification of Sergio Garcia for serious misconduct.

The Spaniard became the first player on the European Tour to be disqualified under Rule 1.2a, which reads "players are expected to play in the spirit of the game by acting with integrity, showing consideration to others and taking good care of the course".