Campbell birdied four straight holes in a 7-under 65 as he continued to show a return to the form that won the 2005 U.S. Open title. He has three top-10 finishes in his past four events after missing 10 cuts earlier this year.
The New Zealander had completed 14 holes Saturday, with a birdie on his last from 15 feet as darkness set in. He then birdied his first three holes Sunday morning.
Westwood, the defending champion, bogeyed his first three holes Saturday, but recovered with two eagles and three birdies over the rest of his round, which was again interrupted after a lengthy fog delay Saturday morning.
He eagled the third hole'his 11th'Sunday with a 5-wood approach to four feet. He birdied the fifth and sixth.
The final round was being played later Sunday.