For the first time in nearly two decades, four American men have marched their way into the second week at the Australian Open.

Tommy Paul, J.J. Wolf, Sebastian Korda and Ben Shelton are all set to make their fourth-round debuts at Melbourne Park, a feat that hasn't happened since Grand Slam champions Andy Roddick and Andre Agassi advanced back in 2004.

“I haven't thought about it too much, honestly, because I just have that one-match-at-a-time mentality, but I think it's hard for anyone to look past that. There's been a lot of upsets,” 67th-ranked J.J. Wolf said after eliminating lucky loser Michael Mmoh 6-4, 6-1, 6-2 in an all-American matchup on Saturday, per ESPN. “But upsets happen for a reason. A lot of people out here are good. It is a real opportunity.”

Wolf will now play another fellow American in the 89th-ranked Ben Shelton, who won the NCAA title while playing for the University of Florida as a sophomore last year before turning pro. He defeated wild-card Alexei Popyrin 6-3, 7-6 (4), 6-4 in the third round.

Tommy Paul, ranked 35th, defeated yet another American man, Jenson Brooksby, 6-1, 6-4, 6-3 in this third-round match. He will play Roberto Bautista Agut next week, after the Spaniard defeated three-time Grand Slam champion Andy Murray on Friday.

Sebastian Korda upset a Grand Slam champion of his own in No. 7 Daniil Medvedev in an impressive straight sets victory, 7-6 (7), 6-3, 7-6 (4), and will play Hubert Hurkacz next.

Novak Djokovic now remains as the last player among the final 16 who have won a Grand Slam title, and World No. 3 Stefanos Tsitsipas is the only other man who has played in a title championship, losing to the Serbian superstar in the 2021 French Open final.

Early losses by No. 1 Rafael Nadal, No. 2 Casper Ruud and No. 7 Medvedev have truly opened the field in Melbourne, and there's a very real chance that at least one of Paul, Wolf, Korda or Shelton could make it as far as the 2023 Australian Open final.