Novak Djokovic came from a set down to book a quarter-final place but second seed Andy Murray crashed out in less than an hour at the Monte Carlo Masters.
Djokovic pulled through against Juan Monaco to join third seed Rafael Nadal, who beat Philipp Kohlschreiber in straight sets.
However, that was in sharp contrast to the fortunes of US Open champion Murray, who won only three games against Stanislas Wawrinka, with Tomas Berdych and Juan Martin del Potro – the fourth and fifth seeds respectively – also exiting the tournament.
Djokovic was forced to come from behind for the second day in a row and credited his “inner strength” after beating Monaco 4-6 6-2 6-2.
The Serbian, who had been tested by Mikhail Youzhny in the second round, lost serve four times as he battled past Monaco in just over two hours to book a tie against Finn Jarkko Nieminen, Del Potro’s conqueror.
It is his first clay-court tournament of the year and comes less than a fortnight after he twisted his ankle during a Davis Cup tie against the United States.
Djokovic said: “It’s another big test obviously, again a two-hour match.
“Obviously I’m not physically out there feeling my best.
“Somehow it feels that I always miss that half a step. But I’m trying, I’m fighting.
“After I lost the first set today [Thursday], I tried to find that inner strength – I found it again so that’s a positive thing.
“Every day brings a new challenge and we’ll see what happens tomorrow [Friday].”
Second seed Murray was demolished 6-1 6-2 by 13th seed Wawrinka, who won 75 per cent of his service points and broke his higher ranked opponent five times to record his fifth win in 13 meetings with the Scot.
Murray, who made 24 unforced errors, told a post-match press conference: “When I started making a lot of errors he was able to dictate all of the points from there.
“I’ve played some good tournaments here but it does take me time to feel comfortable on the surface. I need matches against top players to see what’s going wrong and going right and the things I need to work on to get better.”
Wawrinka said: “He’s an amazing player. He’s always tough to beat.
“Therefore, to beat Andy that easy was a big surprise, for sure.
“He’s playing slow, he’s playing from the baseline, he’s not putting so much pressure. For me on clay, it’s perfect.”
Wawrinka will now play sixth seed Jo-Wilfried Tsonga who breezed past Jurgen Melzer 6-3 6-0.
Nadal’s bid for a ninth successive Monte Carlo Masters crown remained on track as the third seed swept into the last eight by defeating Kohlschreiber.
Nadal was rarely troubled by the German, turning in a typically dominant clay court performance to see off the world number 21 6-2 6-4 in 81 minutes.
He will next face Grigor Dimitrov, who continued his improved form of late with a 6-2 6-4 defeat of Florian Mayer.
Fourth seed Berdych was surprisingly ousted 6-4 6-2 by Italian Fabio Fognini and he was followed by Del Potro, beaten 6-4 4-6 7-6 (7/4) by Nieminen in two hours and 38 minutes.
Nieminen missed a match point at 4-5 in the third set, but broke for a 6-4 lead in the deciding tie-break and closed out victory as del Potro hit a forehand wide.
France’s Richard Gasquet advanced to the quarter-finals with a 7-5 6-4 victory over ninth seed Marin Cilic.
