(CNN) -- Reigning champions Rafael Nadal and Maria Sharapova successfully began the defense of their titles at the French Open on Monday, a day when local player Gael Monfils stole the show by upsetting fifth seed Tomas Berdych.
Nadal was the first on court, with his seven-month injury layoff making this the Spaniard's first grand slam match since being sensationally knocked out of Wimbledon last year by Lukas Rosol.
With six titles in eight finals since his return in February, Nadal had been expected to cruise past Germany's Daniel Brands, 25.
Instead, a man seeking a record eighth title at Roland Garros proceeded to do something he had never previously managed in the first round of a grand slam match - lose the opening set.
This was unwanted history in his 34th grand slam tournament but a reminder of Nadal's dominance in Paris was underlined by this being only the 15th set he had lost in 54 matches at Roland Garros.
The big-hitting Brands, ranked 59th, unleashed a fearless barrage of attacks off both sides and even led the second set tie break 3-0 only for Nadal to claim the set en route to a 4-6 7-6 (7-4) 6-4 6-3 victory.
"He was playing unbelievable. I tried to find my game and tried to resist his fantastic shots," said Nadal, who will face Martin Klizan of Slovakia for a place in the last 32.
"He played a great match and put me in a tricky situation."
There were no such troubles for Sharapova who brushed Taiwan's Hsieh Su-Wei aside in just 54 minutes.
Surrendering only eight points on her serve, the second seed hit just four unforced errors as she set up a second round clash with Canadian teenager Eugenie Bouchard.
The Russian was joined in the next round by three former champions: Li Na, Svetlana Kuznetsova and Francesca Schiavone.
One player not expected to be joining such heavyweights was Slovak veteran Zuzana Kucova, who finally won a grand slam match after 12 years of trying.
The 30-year-old produced a massive shock, knocking out local favorite and 24th seed Julia Georges in a 7-6 (10-8) 6-0 victory.
After being off the tour for the last 18 months, Kucova is ranked 1,152 in the world but made the first round after coming through qualifying.
She will take on Virginie Razzano in the second round, with the French player having enjoyed her greatest success when upsetting Serena Williams in the first round of last year's French Open.
Kucova will struggle to beat Monfils for local press coverage though after the wild card knocked out fifth seed Tomas Berdych in a five-set thriller, winning 7-6 (10-8) 6-4 6-7 (3-7) 6-7 (4-7) 7-5 to delight a partisan crowd.
The match took just over four hours and saw Monfils, currently ranked No. 81 after a knee injury forced him out of the world's top 100, dig deep to win the fifth after losing two tie breaks that could have finished the match early.
World No. 2 Andy Murray, who withdrew ahead of the tournament because of injury, was among those impressed by the Frenchman's display against the 2010 semifinalist.
"You got to love Monfils," the Scot tweeted. "Great entertainer, one of the most fun guys to watch and he's also a really good person."
Berdych's defeat means that three of the world's top 10 are no longer in contention, as the world No. 6 joined the injured Murray and Juan Martin del Potro in being forced to watch on from the sidelines.
A semifinalist himself in 2008, Monfils, 26, faces Ernests Gulbis in the second round while fellow Frenchman Jo-Wilfried Tsonga eased through with victory over Aljaz Bedene.
No Frenchman has won at Roland Garros since Yannick Noah in 1983.
In other notable results on Monday, grand slam debutant Nick Krygios of Australia beat Czech veteran Radek Stepanek thanks to a 100% record in the tie breaks - the 18-year-old winning 7-6 (7-4) 7-6 (10-8) 7-6 (13-11).
At one point in the second set tie break, the winner of this year's Australian Open junior event trailed 6-0.
And after sporting a new blonde hairdo during her routine defeat of Israel's Shahar Peer, Agnieszka Radwanska was refreshingly frank when asked what she knew about her next opponent, American Mallory Burdette.
"To be honest, not much. Nothing at all, actually," the fourth seed from Poland said with a smile. "I might Google her.''
Should she beat the 22-year-old, Agnieszka may not have to do much work about her potential opponent in the third round - younger sister Urszula, who must beat Dinah Pfizenmaier of Germany first.