The US Open men's draw is a land of opportunity for a host of unfancied names after Marin Cilic became the latest favourite to crash out.
Andy Murray’s withdrawal left Cilic as the only player in the bottom half to have won one of the sport’s biggest titles and one of only three previous slam finalists.
But the Croatian came into the tournament having not played a match since losing the Wimbledon final to Roger Federer because of an adductor problem.
The lack of match play appears to have cost him, with Argentinian Diego Schwartzman winning 4-6 7-5 7-5 6-4.
It was a landmark victory for Schwartzman, one of the smallest men on the tour at 5ft 7in, who is through to the fourth round at a slam for the first time.
And he, along with all the other players in the half, will now see it as a huge chance to go all the way to the final.
With previous finalists David Ferrer and Jo-Wilfried Tsonga both losing early, only Sam Querrey has even made a slam semi-final, while his fellow American John Isner is the highest seed left at 10.
Schwartzman said: “Sometimes if you have luck in the draw and you can take the chances, it’s always good for the new guys or for the guys who are outside the top 10.
“I think many players are doing well this week, and they are taking the opportunities. Many (top) players are injured this week.
“I am a little bit surprised to be in the fourth round but the last weeks I was playing really well. My confidence is going up. I think in every match I can win.”
Schwartzman, who next meets 16th seed Lucas Pouille, is happy to be an inspiration for smaller players.
He said: “I hope maybe they can understand tennis is for everyone. It’s not just for the tall guys.”
Pouille, a quarter-finalist last year, came from a set down to defeat Mikhail Kukushkin 2-6 6-3 6-4 6-4 while a name all the players will be wary of is 18-year-old Denis Shapovalov.
The teenager is the youngest man to reach the fourth round of a grand slam in nearly 20 years and looks to be heading quickly for the top of the game.
After beating Tsonga in round two, Shapovalov had a stroke of luck when third-round opponent Kyle Edmund suffered a back problem during the third set and pulled out with the Canadian leading 3-6 6-3 6-3 1-0.
Shapovalov was one of two teenagers through to the third round along with Russia's Andrey Rublev, who takes on Damir Dzumhur on Saturday.
The 18-year-old Shapovalov said: “We’re definitely making an impact. I think in a year or two, the rankings are really going to change. There are a lot of young guys coming up, and the tour has got a lot of veterans right now. It’s kind of a transition time.
“Every grand slam, it’s a chance for young guys to prove themselves and I have been doing that. Hopefully I can keep doing that. I think everyone is beatable.”
Shapovalov next faces 12th seed Pablo Carreno Busta, who finds himself in the unprecedented position of taking on four successive qualifiers.
Croatian Borna Coric could not follow up his big win over fellow 20-year-old Alexander Zverev, losing 6-4 6-3 6-2 to 28th seed Kevin Anderson.
