Holder Stefanos Tsitsipas moved into the Monte Carlo Masters quarter-finals with a 7-5, 7-6(1) victory over Laslo Djere on Thursday while fourth seed Casper Ruud was knocked out in straight sets by Grigor Dimitrov.
Tsitsipas broke only once in a match where break points were in short supply but the Greek third seed pounced when it mattered most at the end of both sets to seal victory.
The opening set went with serve but Djere was nearly broken when he was down 5-4 after he made three double faults. Djere held on but Tsitsipas switched gears and broke him in his next service game when the Serbian fired wide on set point.
The second set was nearly identical to the first with just one break point between the two. This time Djere forced a tiebreak, but Tsitsipas was unstoppable as he took the first five points before sealing the match with a forehand winner.
"I knew that I was going to have to be alert and 100%, he's someone that can compete very well on clay... I really had to work hard for this win," Tsitsipas said in an on-court interview.
"The beginning of the tiebreak was very important to get such a good, dynamic start... I was able to dictate those rallies and really get ahead of the game early on."
Diego Schwartzman stole the show on the day, however, after the Argentine fought back from a set down to beat Lorenzo Musetti 2-6, 6-4, 6-3, receiving a standing ovation from the crowd after the 2-1/2 hour contest.
Schwartzman was 3-1 down in the second set when he found a second wind and stormed back into the contest, winning 11 of the next 15 games to book a quarter-final clash with Tsitsipas.
Second seed Alexander Zverev fired eight aces and smashed 26 winners to beat Pablo Carreno Busta 6-2, 7-5 on the back of a strong first serve.
"On claycourts, especially here where it's a little slower compared to other claycourts we play on, it's very important to get that confidence going on your serve," Zverev said.
Zverev will take on Jannik Sinner, who rallied from a set and a break down to upset last year's finalist Andrey Rublev. The Italian converted seven of his 12 break points and saved six of 10 en route to a 5-7, 6-1, 6-3 comeback win.
Earlier, Norwegian Ruud became the tournament's latest high-profile casualty as he went down 6-3, 7-5 to Bulgarian Dimitrov, who moved into the quarter-finals for a fourth time.
"It's always tough this week because you're switching surfaces," Dimitrov said. "So I try and not be too tough on myself in practice. I just try to do the simple things. It's going so well so far."
Unseeded Spaniard Alejandro Davidovich Fokina, who beat world number one Novak Djokovic earlier this week, reached the last eight with a 6-4, 6-1 win over David Goffin.
He will meet 10th seed Taylor Fritz, who beat doubles partner Sebastian Korda 7-6(4), 7-5 in a battle of Americans.
"I fought off his returns on my second serves, which was the main focus. It was really good conditions today, so I was able to play what I felt was my best match," Fritz said.
