Westwood had birdies at the first five holes to move to the top of the leaderboard at 12-under 204.
Im going to play a round under the pressure of trying to win tomorrow, and thats what I wanted, Westwood said.
The English Ryder Cup player sank putts of six, 12, 15 and eight feet by the fourth and two-putted from 20-feet at the par-5 fifth.
Oliver Fisher rolled in a 35-footer at the par-4 18th to finish with a bogey-free 67. The 19-year-old is at 11-under 205.
I have a chance now and Ill just go out and try and do the same things, he said. Winning this season was definitely a goal.
Fisher was joined by fellow Englishman David Lynn (68) and Frances Thomas Levet (68) at 205.
Morning leader Peter Hedblom (70) of Sweden trailed by two shots in fifth.