World number two Jordan Spieth wasted no time in doubling his experience of the Old Course at St Andrews ahead of this week's Open Championship.
Spieth is halfway towards an unprecedented calendar grand slam after winning the Masters in April and the US Open last month, but only arrived at the Home of Golf on Monday afternoon after beating Tom Gillis in a play-off for the John Deere Classic in Illinois on Sunday.
The 21-year-old, who had played just one previous round at St Andrews in 2011, headed straight to the course and played all 18 holes, interrupted only by a chat with former world number one Tiger Woods - who won the Open here in 2000 and 2005 - on the 16th green.
Woods had been playing alongside Jason Dufner, Matt Kuchar and Gary Woodland, but while that trio continued to the famous 17th, Woods stayed back to putt on the 16th as Spieth approached.
Spieth - who attempted several shots off the wall behind the Road Hole - did not speak to the media after finishing his round shortly before 9pm, but did sign autographs for fans and told them he was "a little tired" after not sleeping for 48 hours.
England's Paul Casey believes jet-lag could be the biggest barrier to Spieth contending this week, but the American certainly appeared relaxed during his round, throwing himself to the turf and rolling on his back when he missed a putt on the fifth green.
"The only thing that's going to be against Jordan would be the jet-lag," said Casey, who finished third the last time the Open was held at St Andrews in 2010.
"I think you can argue either way for playing links (golf) the week before or not playing links the week before. Fatigue is going to be the only thing that gets in his way from having a great championship this week.
"He's young enough where he'll probably overcome it with a good night's sleep. I've tried it various ways, playing the week before, not playing the week before, and I think ultimately it depends on how you play and the attitude you carry coming out of the event.
"Coming off a win like he is from last week, that's massive momentum. He certainly hasn't done any damage. We'll see how it pans out come Thursday."