Denny Medley-USA TODAY Sports

Several sports stars took part in the American Century Championship last weekend -- which is a celebrity golf event that takes place in Lake Tahoe. A few current NFL stars that played in the event were Minnesota Vikings star wide receiver Adam Thielen, Vikings cornerback Patrick Peterson, Green Bay Packers quarterback Aaron Rodgers and Kansas City Chiefs signal-caller Patrick Mahomes. There was a moment during the final day of the tournament that went viral, which included Mahomes speaking about a new rival.

As Mahomes was walking to his ball on Sunday, a fan yelled out and told the star quarterback, "Watch out for Justin Herbert next year!"

Here's how Mahomes responded:

"I'll see it when I believe it," quipped Mahomes with a smile. He likely meant to say, "I'll believe it when I see it," but his point was made.

The Los Angeles Chargers made Herbert the No. 6 overall pick in the 2020 NFL Draft last year, and the young quarterback impressed in his very first season. He was even named the 2020 AP Offensive Rookie of the Year after throwing for 4,336 yards, 31 touchdowns and 10 interceptions in 15 games played. While he went 6-9 as the starter, Herbert's 31 passing touchdowns were an NFL rookie record, and his 289.1 passing yards per game also set a rookie record and were the fourth-most this season overall.

Interestingly enough, Herbert's first NFL start came against the Chiefs in Week 2. After a team doctor reportedly punctured Tyrod Taylor's lung by accident prior to the game, the rookie was thrust into the starting lineup against the reigning Super Bowl champions. Herbert was ready for the moment, however, as he threw for 311 yards, one touchdown and one interception, and also rushed for another touchdown before the Chargers ultimately fell to the Chiefs in overtime, 23-20.

Herbert didn't get a chance to face off against Mahomes again, as the latter was benched in the season finale to rest in what was a meaningless matchup, but Herbert did throw for 302 yards and accounted for four total touchdowns as Los Angeles defeated Kansas City's backups, 38-21.

It's unlikely that the Chargers are ready to unseat the Chiefs in the AFC West just yet, but they do appear to have found their quarterback of the future -- and that's certainly something. Herbert and Mahomes will likely be able to face off two times a season for years to come, and the Oregon product will soon enough make Mahomes a believer.