Daniil Medvedev has dug deep to fight off a charging Filip Krajinovic, but extended his winning streak to 17 matches and joined the Russian charge into the Australian Open fourth round.
The frustrated fourth seed forced coach Gilles Cervara from the otherwise empty stands at Rod Laver Arena with a couple of verbal volleys, after dropping his first set of the tournament and falling a break down in the fourth.
Krajinovic, who spent his pre-tournament quarantine practising with world No.1 Novak Djokovic, found success preying on Medvedev's forehand and rode the momentum to send the contest into a fifth set.
But a second trip to the toilets did the trick for Medvedev and he broke the Serbian for 2-0 in the decider with a crunching forehand winner, winning 6-3 6-3 4-6 3-6 6-0 to seal a last-16 date with American Mackenzie McDonald.
The 25-year-old, who had lost his six previous five-setters, joined compatriot Aslan Karatsev in the fourth round, after the qualifier manufactured a stunning straight-sets upset of Diego Schwartzman on Friday.
With seventh seed Andrey Rublev and Karen Khachanov also in action on Saturday, Russia could end up with an open-era record four men in the last 16 of a Grand Slam.
But among the women, Karolina Pliskova never found her comfort zone, as the sixth seed exited with a 7-5 7-5 third-round defeat to Czech compatriot Karolina Muchova at Rod Laver Arena.
Pliskova's frustrations boiled over in the first set, as she received a code violation for racket abuse and was then handed a point deduction for smashing another racket in the tunnel between sets.
Pliskova says she was a little bit surprised at the second warning, but that it had had a positive impact on her game.
"I think actually it helped me in the second set, because I was [annoyed], so I started to play well," she says.
After losing the opening set, Pliskova raced to a 5-0 lead in the second, before the wheels came off, allowing Muchova to complete the victory and reach the fourth round in Melbourne for the first time.
"There was long game for 5-1 and 6-0," Pliskova adds. "I thought she just played little bit better at this moment.
"Of course, I played quite amazing to 5-0, but then it's quite tough to hold this level.
"I had chances... on my serve, I just could do so many things better today. I don't think my game is the top for sure.
"I don't want to be too sarcastic and too negative, because I just lost. The feeling was not great from any of my matches here.
"I think, overall, too many mistakes, too much panic in the rallies. I don't know if it's just not having any matches much lately.
"I don't feel like safe with anything I was doing on the court."
Muchova, the world No.27, next faces either Switzerland's Belinda Bencic or Elise Mertens of Belgium for a place in the quarter-finals.