World number one Rory McIlroy showed no ill effects from the ankle injury that threatened his season with an opening round of 71 to sit five shots off the lead held by Dustin Johnson at the US PGA in Wisconsin.
The Holywood golfer missed the Open championship last month after rupturing ankle ligaments while playing football with friends but returned to defend his title at Whistling Straits and carded an impressive round of one under par, as did double major winner Jordan Spieth.
Speaking after his round that contained four birdies, McIlroy said that his "ankle feels great".
McIlroy’s compatriot Graeme McDowell was left to rue a late run of missed putts with three bogeys in his last three holes to end his round on one over par.
The highlight of the day was saving par on the fifth after playing his fourth shot from the edge of a water hazard, McIlroy simply rolling up his right trouser leg and splashing out of the shallow water to 12 feet.
"The only thing I was trying not to do was get my feet wet, because if the water gets through this shoe, then the tape [on his left ankle] gets wet and then that would be annoying or uncomfortable for the rest of the day," McIlroy said.
"It was a little bit deeper on the right side, so I just rolled my right trouser leg up and it was fine. I just had to remember to hit it hard. And I was very fortunate to escape with a par there.
"I think anything under par this afternoon was a decent score. I thought trying to shoot something under 70 was realistic. I sort of had a chance to do that after birdieing the 16th. I missed a good chance there on 17. Unfortunate bogey on the last, I guess. Just hit a 3-iron and held it up a little bit too much into the wind and leaked it right."
Padraig Harrington, the 2008 winner, shot a four-over-par 76.
Last week’s WGC Bridgestone Invitational winner Shane Lowry came back down to earth with a six-over-par 78, the same score as European Ryder Cup captain Darren Clarke.
Johnson admitted an opening 66 was as easy as he made it look, but the hard part will be converting that into an overdue first major title after numerous near misses.
Johnson carded an eagle, five birdies and a solitary bogey to set a testing clubhouse target as a strengthening wind made conditions difficult for the later starters.
At six under par, Johnson held a two-shot lead over a seven-strong group which included playing partner Jason Day and Matt Kuchar, with English pair Justin Rose and James Morrison another shot back on three under.
Tiger Woods, who missed consecutive cuts in majors for the first time ever in the US Open and Open Championship, faces another early exit after struggling to an opening 75.
Sweden's David Lingmerth defied the conditions to reach six under after covering the back nine in 31 and picking up another shot on the fifth, only to promptly three-putt the sixth for his first bogey of the day.
The last time the US PGA was held at Whistling Straits in 2010, Johnson was one shot ahead with one to play and thought his bogey on the 18th meant he would be heading into a play-off with Martin Kaymer and Bubba Watson.
However, the 31-year-old was then penalised two strokes after it was ruled he had grounded his club in a fairway bunker before hitting his second shot, even though spectators had been trampling all over the hazard.
Johnson had also squandered a three-shot lead in the final round of the US Open two months earlier and he three-putted the 72nd hole at Chambers Bay this year to finish a shot behind Jordan Spieth.
The world number eight, who led after the first and second rounds of the Open before fading badly at St Andrews, started on the back nine and made birdies on the 10th and 11th before holing from 30 feet for an eagle on the 16th.
Further birdies on the first and second were followed by a bogey on the third, where playing partner Rickie Fowler needed four shots to escape a bunker and took seven, but Johnson bounced straight back with a birdie on the fourth.
"Today was pretty easy, I would have to say," Johnson said. "I was swinging well and I was hitting the shots where I was looking and I really felt like I was just super patient, stayed focused all day.
"I played pretty well at the US Open on the weekend. At the British Open I didn't play well on the weekend, but even the first two days I didn't feel like I was playing that good golf. I wasn't too comfortable with my swing. I wasn't hitting the shots that I wanted to hit. I didn't feel like I was too much in control.
"Today, I really felt like I had my ball under control a lot like I did at the US Open. We'll just have to see what happens. It's only the first round, we've still got a lot of golf to play."
