Australian No.1 Alex de Minaur and Russian top-10 star Andrey Rublev charged into the third round of the Australian Open on a day where the big names were anything but safe at Melbourne Park.
Rublev and De Minaur restored some order to the Thursday schedule, as did No.20 seed Taylor Fritz, a straight-sets winner over fellow American Frances Tiafoe.
MORE: All the scores from Day 4 at AO 2022
But 13th seed Diego Schwartzman was stunned by Australian wildcard Chris O'Connell, while former world No.3 Grigor Dimitrov fell to French nemesis Benoit Paire.
Canada's Felix Auger-Aliassime survived a four-hour, 19-minute struggle, amid 83 unforced errors, to eventually get past Spaniard Alejandro Davidovich Fokina.
De Minaur made his return to Rod Laver Arena after a three-year absence and scored his first ever victory on the tournament's premier court.
He beat Poland's Kamil Majchrzak 6-4 6-4 6-2 and has now won six consecutive sets at AO 2022 after dropping the first in his opening-round win over Lorenzo Musetti.
De Minaur, the No.32 seed, next plays unseeded Spanish veteran Pablo Andujar for a spot in the last 16 for the first time.
"For me to be able to play on that court (Rod Laver Arena) and at this stage be on my own merits, it's not because I'm playing one of the top guys, that's a pretty cool feeling," De Minaur said. "A very solid win. Came out, did everything I needed to do. Got the job done. Very happy with my effort."
Earlier, Rublev trounced Ricardas Berankis 6-4 6-2 6-0 in the first match of the day at KIA Arena, at the same time fellow big names Garbine Muguruza and Anett Kontaveit were being upstaged on nearby stadiums.
MORE: Women's singles results AO 2022
The world No.6 belted almost twice as any winners as Berankis (35-18) while committing 17 less unforced errors in an assured performance to maintain his unbeaten start to the season.
He was forced to skip the ATP Cup earlier this month as he recovered from a bout of COVID, and will undergo a real test of his level when he comes up against former US Open champion Marin Cilic in the third round.
Cilic was a four-set winner over Slovakian qualifier Norbert Gombos.
Auger-Aliassime took a step closer to a potential fourth-round meeting with Rublev after finally seeing off the 50th-ranked Davidovich Fokina in four tiebreaks.
The No.9 seed needed four set points to finish off the third set, and recovered from a break down in the fourth, before eventually cementing victory with a lunging forehand volley winner.
"Definitely getting plenty of tennis so far this week," said the 21-year-old, who needed five sets to beat Emil Ruusuvuori in round one.
"Crazy match it was. I mean, credits to Alejandro. I know him from juniors way back and he's a great guy, tough opponent. He showed up with a great level today.
"(I’m) just happy that it fell on my side. (It’s a great result) when you play four tiebreaks in a row and I was able to win three out of four."
Standing between Auger-Aliassime and a spot in the second week is Brit Dan Evans, who advanced when Frenchman Arthur Rinderknech withdrew ahead of their match with a wrist injury.
At around the same time Auger-Aliassime prevailed, Paire completed an upset victory over 26th seed Dimitrov.
The 32-year-old, a former top-20 player now ranked No.56, won 6-4 6-4 6-7(4) 7-6(2) – his fourth victory in five meetings over the Bulgarian.
Paire has not ventured this deep at a Slam since reaching the fourth round at Wimbledon in 2019, and next faces No.4 seed Stefanos Tsitsipas for a chance to match that result.
Fritz, meanwhile, notched a 6-4 6-3 7-6(5) win over Tiafoe, who received a visit from the trainer to work on his right shoulder.
Fritz also had physical issues, but they came at the last minute – he smacked a backhand winner down the line to seal match point and fell to the court as his right calf cramped.
"Frances is one of my really good friends, and he's such a good guy. I said before the tournament too, he's probably one of the most, if not the most dangerous unseeded player in the draw," said Fritz, who meets No.15 seed Roberto Bautista Agut in the third round.
"I just wanna keep playing my game, keep playing aggressive, like that last point... I've got a really tough match next round, but it would be awesome to have a deep run here."
Schwartzman's loss was somewhat perplexing, given the Argentine had won three of his four matches so far in 2022 and looked solid in a straight-sets first-round outing against dangerous world No.36 Filip Krajinovic.
"Not many positive things about the match. It was a difficult match for me, and I think he did great on court, and he deserved the win. But I didn't do a very good match," Schwartzman rued.
But it was a magnificent day for the 175th-ranked O'Connell, who advanced to the third round of a Grand Slam tournament for the first time in his career.
There awaits Maxime Cressy, the American captivating fans with his throwback serve-and-volley style and who eliminated Czech qualifier Tomas Machac in four.
Also advancing the third round was Dutchman Botic Van De Zandschulp, after opponent Richard Gasquet retired in the third set of their clash.
Van De Zandschulp, a US Open quarterfinalist last year, next faces second seed Daniil Medvedev – the man who ended his compelling run in New York.
In the final men's match played on Thursday, Italian Jannik Sinner extended his head-to-head record over American Steve Johnson to a perfect 3-0 with a methodical 6-2 6-4 6-3 victory.
Sinner, the 11th seed at AO 2022, meets Taro Daniel in the third round, after the Japanese qualifier took down five-time Australian Open runner-up Andy Murray in straight sets.