Westwood had a bogey at the second hole but countered that with five birdies, including three in a row over Nos. 11-13. He is at 16-under 200 after 54 holes.
Ross Fisher, who is yet to have a bogey this week, fired a 7-under 65 and moved into second place at 13-under for the tournament. Peter Hanson was 3-under Friday and is in third four strokes behind Westwood.
Westwood rode an 8-under 64 Thursday into a 3-stroke lead. He opened with a birdie but then had a bogey at the second hole -- just his second bogey of the tournament. He got that back at No. 4, however.
Fisher got within one stroke after posting four birdies in a five-hole span over Nos. 12-16 but Westwood, playing a few groups back, answered with his birdie run over 11-13.