Willett birdied the final three holes over the re-designed West Course at the Wentworth Golf Club. The tournament is one of the highlight attractions on the European Tour calendar.
Ernie Els, who was in charge of the reworking of the course, bogeyed the 18th and shot a 69.
"Right now I'm disappointed, but overall the course played fair and very well," Els said. "The way it was set up gave people the opportunity to make birdies and that's what we had in mind."
Ten of the top 25 players in the world competing at Wentworth this week.