Australia's Stuart Appleby is only one shot off the lead after the first round at the PGA Tour's FedEx St Jude Classic.
He is in a big group of players on four-under 66, that also includes multiple major winner Phil Mickleson.
They all sit behind Ireland's Seamus Power on five under.
Mickelson said he became ragged off the tee late in his round but avoided any damage at TPC Southwind in Memphis.
"I finished the round off, even though I didn't quite have it there at the end," Mickelson told PGATour radio. "I had a nice simple round going and then I missed the last four fairways.
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"I was able to gather myself well and control my thoughts a little bit better."
By playing in Memphis, the 47-year-old is continuing his traditional build-up for the US Open, which he has come second in six times but never won.
It's the only major he needs to complete a career grand slam.
Meanwhile, defending US Open champion Brooks Koepka matched Mickelson's 66 on Thursday, saved by a putter that was almost as hot as the Memphis weather.
"I didn't play well at all," he said. "We were all over the place. I'm a good putter. I just need to figure out everything else."
World number two Dustin Johnson also started well with a 67 that included a chip-in birdie at the par-four 12th.
After his approach shot ended in a hazard but dry, Johnson removed his right shoe and sock, took his stance in the mud and choked down on his wedge, before knocking the ball into the hole.
"I actually didn't hit it very well and got lucky and it went in the hole," he said modestly.
Leader Power, an Irishman who went to university in Tennessee, capped off his day by hitting his approach shot to five feet for a birdie at the last.
