MEMPHIS, Tenn. – Four days ago, Jon Rahm was enduring the season’s worst weather conditions on Sunday at The Open on his way to a closing 75 at Royal Portrush, which considering the wind and the rain was a respectable showing.

Thursday’s first round at the WGC-FedEx St. Jude Invitational was another story. With temperatures in the mid-80s and hardly any wind, the Spaniard was 13 strokes better in a flawless round.

Thanks to his best putting performance on the PGA Tour, Rahm finished with an 8-under 62 for a three-stroke lead, which was even more impressive considering he’d never played the front nine at TPC Southwind.

“The main key out of all that, it was my positioning,” Rahm said. “The putt on [Nos.] 1, 2, 7 and 8, those birdie putts that I made, not any of them were aimed outside the edge right or left. So that's what made it so, not easy but that's what made it so comforting.”

Rahm finished with a career-best strokes gained: putting average (5.203) that included 18-footers for birdie at Nos. 1 and 2 and a 16-footer for birdie at No. 7.

It was an impressive start for a player who admitted to being jetlagged following his flight from last week’s Open Championship in Northern Ireland.

“I tried to put a stress or a little emphasis on being rested and it paid off today,” he said. “Obviously, I have three more days to go and hopefully the battery lasts.”