Both the Englishman and UCLA product shot six under par 65s in Thursday's first round of the 96th PGA Championship outside Louisville, taking the lead after a morning round that featured good scoring conditions.
Westwood, who has come close to winning majors in the past, factored in a good final round last Sunday at the Bridgestone Invitational when it came to his performance Thursday.
"I've played better rounds of golf but I was really pleased with today," Westwood told PGA.com. "I hit a lot of quality iron shots, and it felt like 65 was a fair enough score for the way I played. I got a couple of bad breaks out there, but you know, I rolled a couple of putts in, like the one on 9 that you probably wouldn't expect to hole. But that's just the way it is. A bit of momentum is a wonderful thing."
Friday, Westwood tees off at 1:25 p.m. Eastern time, playing with Jordan Spieth of the US and former Masters champ Adam Scott of Australia.
"I guess I was in a good rhythm out there," Chappell told reporters later. "Drove the ball well. Hit a lot of greens and gave myself some opportunities and I was able to take advantage of it, something that hasn't happened a lot for me this year, but looking forward to building on today and moving forward."
Chappell will start Friday's second round from the tenth hole at 1:30 p.m. Eastern time.
Also at six under par is American Ryan Palmer, who has finished second in two out of 18 PGA Tour events played this season. Palmer tees off the second round at 7:30 a.m. Eastern Friday.
There are five golfers tied for fourth at five under par, including British Open champion Rory McIlroy. The 2012 PGA champ tees off at 8:35 a.m. Friday. Former US Open champion Jim Furyk, also part of the five under crew, tees off at 2:05 p.m. Eastern.
Woods seemed to navigate the Kentucky golf course without any obvious physical problems in Thursday's first round. He shot a three over 74 on the same course where he won the 2000 PGA. Afterwards, he expressed disappointment in his round to PGA.com.
"It wasn't very good," Woods said to the assembled media. "A lot of bad shots and I never got a putt to the hole. I hit them all my lines. Just for some reason I thought they were going to be a little bit quicker, and I didn't make the adjustment well enough."
Tiger will be paired once again Friday with former PGA champions Phil Mickelson, who shot a two under 69, and Padraig Harrington. They will tee off at 1:45 p.m. Eastern.
TNT will televise Friday's golf action, beginning at 1 p.m. Eastern. You can also watch live action during the day streaming on PGA.com.