Jiri Vesely and Damir Dzumhur upset the odds on Wednesday as Novak Djokovic and Tomas Berdych were high-profile causalities at the Monte Carlo Masters.
Czech number one Berdych was stunned in three sets by world number 99 Dzumhur, but his compatriot Vesely celebrated the biggest win of his career against the top seed and defending champion.
Djokovic's departure opens up the top half of the draw nicely, with Jo-Wilfried Tsonga and the returning Roger Federer now eyeing a deep run.
In the bottom half, Stan Wawrinka and eight-time champion Rafael Nadal were comfortable winners, beating Philipp Kohlschreiber and Aljaz Bedene in straight sets respectively.
VESELY POUNCES ON SLOPPY DJOKOVIC
Djokovic was a million miles away from his imperious best on his first appearance on clay this year, struggling to find his range, bar a run of four straight games to see out the second set.
The defeat was his first to a player ranked outside the top 50 since 2010, and his first loss at this stage of any event since 2013.
When asked to reflect on his achievement, Vesely was far from awestruck, immediately looking to how he can use it as a platform to greater success.
"I hope it will give me a lot of confidence, a lot of self-belief. I think I've struggled pretty much the past few months where I really didn't play good tennis," he said. "Obviously last week was the first week of the year where I played a little bit in good form and in good shape. I'm just amazingly happy the way I fought today and the way I finished the match."
NADAL IN THE GROOVE, BUT STERN TEST AWAITS
While Djokovic seemed troubled in his attempts to get to grips with life back on dirt, the King of Clay understandably had no issues.
Bedene proved no obstacle for Nadal as he improved his tournament record to 54-4.
Next up for Nadal is 12th seed Dominic Thiem, who boasts a 26-6 record this season and beat the Spaniard on his way to the first of his two titles this year in Buenos Aries.
"There is always room for improvement. It is obvious that I have been practicing little bit better than what I played today," Nadal said. "But at the same time it's true that I have been playing good for moments, some mistakes in other moments. But it's fine, isn't it?"
WAWRINKA GETS HIS EYE IN
Wawrinka improved his head-to-head record against Kohlschreiber to 4-0 with a dominant display, save for a slight wobble in the second set, beating the German 7-6 (7-2) 7-5.
Titles in Monte Carlo and Roland Garros under his belt, Wawrinka takes on Gilles Simon next, with Nadal likely lurking in the following round.
Wawrinka has won three of his last five meetings with Nadal, including their previous meeting on clay, in Rome last year.
MONFILS ONE TO WATCH
In a top half shaken up by Djokovic's exit, Gael Monfils registered an eye-catching straight-sets win over Paolo Lorenzi.
Just one of Monfils' five Tour titles has come on clay, a victory at the Sopot Open in 2005, but a 6-2 6-4 triumph in just 75 minutes was one of the day's most dominant scorelines.
Conquerors of Nadal have famously found it difficult to follow up their achievements in the next round in recent years and Monfils will be hoping a win over Djokovic results in a similar fatigue for Vesely.