Rory McIlroy admitted he felt nerves on the first tee as he began the defence of his US PGA Championship title after a seven-week injury lay-off.
The World Number One fired an opening 71 in the more testing afternoon conditions at Whistling Straits to sit five off the lead held by Dustin Johnson in his first competitive round since a closing 66 at the US Open Championship at Chambers Bay on June 21.
The Northern Irishman damaged ankle ligaments playing football with friends in early July but had maintained all week that he was good to go and showed no physical problems as he fired four birdies and three bogeys.
"It was a game of two nines, really, just trying to hold on the front nine and then there was a few more chances on the back and I took advantage of the par fives," he said.
"Great to be back, obviously, I was quite nervous on the first tee not having hit a competitive shot in about two months, I think I was always going to be a little bit nervous."
He added: "Ankle feels great, it's felt great all week, it's obviously not an issue and I think you can see how I'm hitting it out there, I can go after it and I have full confidence in it."
After bogeying the first, McIlroy bombed a drive down the par five second and made the green in two before two putts got him back to level par.
He then completed a remarkable save on the par five fifth as his third shot landed in shallow water but he got up and down to save a par.
He could not scramble a par on the eighth but picked a shot back up on the ninth to get to level.
Further birdies followed on the 11th and 16th as McIlroy appeared to find his rhythm but a bogey on the last took the gloss off a fine back nine.
The 26-year-old's shot from the water on the fifth was possibly the save of the day but McIlroy admitted he was just happy to keep his feet dry.
"I got out okay," he said. "I just had to remember to hit it hard enough.
"(My) right shoe got a little bit wet but thankfully they're good and waterproof so it didn't get through to the sock or the foot so it was fine."
McIlroy's playing partners were Masters Tournament and US Open champion Jordan Spieth and Open Championship winner Zach Johnson in what was billed as the marquee group of the day.
Spieth parred his first 10 holes before bogeying the 11th but chipped in at the 12th to get back to level before another birdie on the 16th put him in red numbers.
Johnson's day was not as productive as three birdies and three bogeys had him level at the turn but further dropped shots on the 12th, 13th and 18th saw him finish the day three over.
"It was fun to be a part of, obviously, with Jordan winning the first two majors of the season and then Zach (winning the Open), I had a feeling they were going to throw me into that pairing but it was nice," McIlroy added.
"I hadn't seen Zach since his Open victory so it was good to chat to him about that and it was a nice way to come back and get right into the thick of things."
