The 39-year-old Briton is third in the world, just behind Ryder Cup team mates Luke Donald and Rory McIlroy, heading into the European Tour's flagship event at Wentworth.
"I'd like to play brilliantly this week and for everybody else to play rubbish but that's not going to happen," Westwood said on the eve of the tournament that carries a total prize fund of 4.5 million euros ($5.74 million).
"This is a week I think everybody that plays on the tour looks forward to. It's the jewel in our crown."
Asked if he would rather just win or beat top-ranked McIlroy and world number two Donald in a play-off on Sunday, the Englishman replied: "I'd rather win by 10 strokes - that's very easy to answer."
Westwood, who has never hoisted the PGA Championship trophy, is still kicking himself for losing out to Donald in a playoff last year.
"It should not have gone to a playoff," said the world number three. "I three-putted the 16th in the last round, didn't birdie the 17th going in with a three-iron and then missed a five-footer for birdie at the last.
"I had my chances. It was my own fault."
Westwood was beaten by Donald in sudden death at the 18th hole after his approach shot landed eight feet from the pin but spun back off the green into water.
Course designer Ernie Els has tweaked the par-five closing hole this year, making sure the grass on the fringe of the green is long enough to avoid a repetition.
Westwood also took the blame for his mistake at the 18th in last year's play-off.
"That didn't happen because there should have been rough there," he explained. "It was because the wind was from the right and I ... pitched it further left than I wanted.
"It was a poor shot. That was the reason it went in the water."
Westwood, without his regular caddie Billy Foster this year because of a long-term injury, said Els's constant tinkering was helping the leafy West Course at Wentworth to get better with every passing year.
"Designing and remodelling courses is tricky and sometimes you need a couple of goes at it," said the former European number one.
"I think every year we come back here it is improving and becoming a better test."
Westwood, however, does not seem to be a fan of the Wentworth greens.
"I spent around an hour and three quarters practising my putting yesterday, just getting used to the speed of the greens," he said.
"I've not putted on anything as slow as this for pretty much most of the year."