Westwood is 15-under with a 201 total, followed by Gonzalo Fernandez-Castano of Spain, who shot a 67.
Westwood's third round ended with bogeys at the last two holes -- one day after the Englishman set a course record with a 64.
'On the last two holes I short-sided myself, and it's just one of those things you have to accept,' Westwood said. 'I was trying to make birdie, not bogey, but I'm not particularly bothered. These things happen.'
Louis Oosthuizen of South Africa, who led after two rounds, shot a 66 and was two strokes off the leader. He shares third place with Michael Jonzon of Sweden, who had a 69.
Frederik Andersson Hed of Sweden shot a course record 64, and sits another stroke back.