MEDINAH, Ill. -- PGA Tour rookie Jackson Koivun won't have to wait long to get his first taste of the Presidents Cup.
Koivun, 21, will play with Justin Thomas in the third match of Thursday's opening four-ball (best ball) session of the 16th Presidents Cup at the No. 3 Course at Medinah Country Club. They'll face off against Canada's Corey Conners and Colombia's Nico Echavarria.
"Obviously, making it this quick is really cool and special," Koivun said Wednesday. "But at the same time, when it comes up on the first tee tomorrow, I need to feel like I belong and I'm ready to compete. Just getting comfortable and acquainted with everything."
World No. 1 Scottie Scheffler and Sam Burns, his best friend on the PGA Tour, will play for the Americans in the opening match against Australia's Min Woo Lee and South Korea's Sungjae Im.
Scheffler, who has won 25 times around the world, will try to improve on his 6-11-4 record in three Ryder Cups and two Presidents Cups.
Cameron Young and Xander Schauffele will play Japan's Hideki Matsuyama and Ryo Hisatsune in the second match. Reigning U.S. Open champion Wyndham Clark and Collin Morikawa will battle Open Championship winner Ryan Fox and Adam Scott in the fourth.
Presidents Cup rookie Chris Gotterup and Patrick Cantlay will face South Korea's Si Woo Kim and Tom Kim in Thursday's final match.
U.S. golfers Russell Henley and Jacob Bridgeman are sitting out the first session, along with Christiaan Bezuidenhout and Nick Taylor for the International team.
Koviun, a former Auburn star, had a meteoric rise in his first season on tour this summer, winning the 3M Open in only his third start as a pro on July 26. He qualified for the FedEx Cup playoffs in only five starts and tied for fifth in last week's Biltmore Championship Asheville.
Koivun was one of Brandt Snedeker's six captain's choices, even though he ranked 48th in Presidents Cup points. Koivun is the second-youngest U.S. golfer to make the Presidents Cup team; Jordan Spieth was 20 when he competed in 2013.
"Jackson being a young kid, I feel like he's really kind of found his way on our team really quickly," Snedeker said. "I feel like he's handled the adjustment really well. Justin is just a natural pairing for him. He's somebody he's comfortable with. I think he'll do a great job putting his arm around him and show him how USA golf is meant to be played."
Thomas, who has a sparkling 6-0-0 four-ball record in three previous Presidents Cup, has taken Koivun under his wing the past couple of years, as the rising star prepared for the PGA Tour.
"He's impressive," Thomas said. "He's a really, really good player, first and foremost, but he's a great kid. He's got his head on right. Hats off to his parents; they've done an unbelievable job. He's very, very mature for his age. I think that's something none of us could instill in him in a week."
The Americans have dominated the competition, winning 10 straight times and losing only once in the first 15 President Cups. The U.S. won 18.5-11.5 at Royal Montreal Golf Club two years ago after taking a 5-0 lead in the first session.
"I think everyone comes into these tournaments with optimism," International captain Geoff Ogilvy said. "They're very momentum-based tournaments. I mean, Montreal was an amazing first two days. [Going] 0-5 was a disaster for us, and then 5-0 [in the second session] was a big success. You could never have predicted that, where it takes a long time to get to this stage. We've been thinking about this for a long time, so we're just excited to get going."