Westwood had seven birdies to go with the bogeys for a 5-under-par 67. Only one player -- Joel Sjoholm, who shot 66 -- had a better third-round score. Westwood is at 15-under 201 after 54 holes.
First-round leader Rafael Cabrera-Bello turned in a 2-under 70 in moving into a tie for second at 14-under. Stephen Gallagher and Marcel Siem, who each shot 68 Saturday, are also one stroke back of Westwood.
Rory McIlroy, who shared the second-round lead, is among four players at 13-under. That includes Sjoholm, who was 6-under both Friday and Saturday. Scott Jamison and Martin Kaymer, who both shot 70, are the others at 2-under. McIlroy had an even-par 72 in the third round.
Thomas Bjorn, the other second-round co-leader, had three bogeys in his last four holes to slip to 1-over on the day and 12-under for the tournament.
Westwood opened with the birdies in his first four holes but went bogey-birdie-bogey over holes 6 through 8. He started the back nine with three more birdies in the first four holes and close with five pars.