Jamie Squire/Getty Images
Even at the Masters - where he'll attempt to hold on to a four-shot lead and win his first major championship on Sunday - he knows what it's like to hold a lead with 18 holes to go. Last year he was tied for the lead with Bubba Watson after three rounds, and eventually finished second.
Even off the course, he seems to be making veteran moves.
According to Brian Wacker of PGATour.com, Spieth rented two houses at Augusta for Masters week, and uses one of them as his personal sanctuary.
From Wacker:
"One is for sleeping. The place he can rest, gather his thoughts, find some quiet time if necessary.
"The other is for fun. The place he can hang out in and enjoy time with his parents, brother, friends and anyone else in town from Dallas this week.
"If he walks into the latter and golf is on television, someone immediately changes the channel. It doesn't matter if it's turned to lawn darts or HGTV. Anything but golf."
In 2012 Augusta.com reported that average four-bedroom house rents for $8,500 for Masters week, with prices overall ranging from $2,500 (for a condo) to $25,000 (for a 10-bedroom house).
We've seen players with big leads on Sunday at the Masters crack before. In 2011 another 21-year-old, Rory McIlroy, took a four-shot lead into the final round and ended up 10 shots behind the winner Charl Schwartzl.