Hats off to Carlos Ortiz!
Firing an opening 64 in any World Golf Championship event is impressive.
But shooting that number when dealing with a 14-hour time gap after flying into Memphis from Tokyo... well, that deserves an extra doffing of the cap.
Ortiz was the standout returning Olympian at the WGC-FedEx St. Jude Invitational on Thursday while Marc Leishman also shook off the bodyclock confusion extremely well to record a 65.
But elsewhere, jet-lag appeared to be kicking in.
Rory McIlroy dipped at the finish, racking up a double bogey and a bogey in his final four holes to shoot a disappointing 2-over 72.
And Viktor Hovland also appeared to run out of gas with dropped shots at his 15th and 17th holes to end with a 3-over 73.
Looking at the tee-times on day one, the 19 players returning from Japan were spread fairly evenly throughout the limited 66-man field.
There were 11 groups featuring a single Olympian while four three-balls contained two.
Those who didn't buy into the jet-lag theory would happily have backed any of them to win their three-balls. But would that have been a mistake?
Firstly, let's deal with the 11 Olympians who played in a three-ball with two non-Olympians. Here's where your money went if backing those who played in Japan:
Si Woo Kim - LOST
Viktor Hovland - LOST
Abraham Ancer - LOST
Cameron Smith - LOST
Corey Conners - LOST
Rory McIlroy - LOST
Sungjae Im - LOST
Patrick Reed - LOST
Garrick Higgo - LOST
Shane Lowry - LOST
Joaquin Niemann - LOST
And how about the three-balls which featured two Olympians? Obviously both couldn't win the group but let's list their results anyway:
Paul Casey - LOST
Carlos Ortiz - WON
Tommy Fleetwood - LOST
Marc Leishman - WON
Collin Morikawa - LOST
Hideki Matsuyama - LOST
Xander Schauffele - LOST
Justin Thomas - WON
That's pretty comprehensive!
Of the 19 Olympians who teed it up in round one, just three won their three-balls.
And all three were in groups which featured two Olympians, making it more likely that one of them would win.
Looking from another betting angle, there was a case for thinking the Olympians may get by on adrenaline on day one before the tiredness hit them later in the week.
Well, backing them for first-round leader wasn't a great idea either.
When the scores were totted up, 10 of the top 12 players on the top of the leaderboard didn't go to Japan. That included leader Harris English (-8), who watched the action on TV.
It's still worth keeping an eye on what happens as the week progresses.
But so far, those who said they would be wary about backing the Olympians due to the jet-lag factor are winning the argument.