Rafael Nadal recovered from the shock of losing the first set of his French Open title defence to world number 59 Daniel Brands by battling into the second round at Roland Garros.
Spain's Nadal - a seven-time champion in Paris - was stunned by the wicked serve of German hopeful Brands and lost the first set of a first-round match at a grand slam event for the first time in his career.
Brands threatened to take the second set, too, only to lose his concentration during a tie-break that handed the initiative back to the world number four, who steadily resisted the German's big hitting on his way to a 4-6 7-6 (7/4) 6-4 6-3 victory.
Since his return from an eight-month lay-off with a knee injury the Spaniard has won eight titles but he made an unconvincing start against 25-year-old Brands, only reaching 4-3 on his serve thanks to some fine groundstrokes.
The scoreline certainly suggested Brands had been holding his own and Nadal's poor forehand into the net gave him the crucial break point before a double-fault allowed him to serve for the set.
And Nadal returned to his chair dejected when Brands smashed a forehand winner down the line to take the first set 6-4 against the defending champion.
It was only the 15th set Nadal had lost in his 54 matches at Roland Garros.
Nadal's service game did not let him down in the second set but Brands was not budging either as the pair traded blows.
The match continued at breakneck speed and to serve with a tie-break following the recovering third seed's surprise failure to break the German in a tense 10th game.
And, despite his perseverance with a forceful approach, Brands threw away a two-point lead in the breaker to let his opponent streak back and take the second set.
The swagger returned to Nadal's step from that point forward and, after consolidating an early break in the third set, he resisted the snap on Brands' forehand to push on to a 6-4 win.
A break in the opening game of the third set had turned the tide in Nadal's favour and he managed to repeat the trick in the fourth when Brands netted a forehand.
Brands kept his side of the scoreboard ticking over with a range of classy forehand winners but a clutch of love services saw a relieved Nadal over the line.
The fourth seed felt his troubles were largely down to the brilliant play of his opponent and expressed disbelief that Brands is ranked so low.
Nadal said: "I think that he arrived on the court completely decided upon striking all the balls, 100 per cent, and he was inspired today.
"He was just firing on all cylinders. He had a fantastic tactic. Maybe my tactic wasn't very good. I don't know where Brands is in the rankings but I can tell you that he can't be 60th. The way he played, I just don't believe it.
"He made me suffer. I can tell you, and I'd like to pay tribute to what he did. I'd like to wish him every success, everything that he deserves for the future."
Nadal's philosophy, instilled in him by his coach and uncle Toni Nadal since he first picked up a racquet, has always been never to underestimate any opponent.
"You have to fight and you have to suffer, and that's exactly what I went through," said Nadal.
"I think throughout my entire career, I have experienced many matches of this type. These are things that you just have to take on your chin in a career and accept once again.
"You have to have sufficient humility just to recognise that your opponent at that particular point in time is playing better than you and you have to wait for the situation to change and find a solution that you can hammer home and then be totally focused.
"I think that's the only way that you can get through a match such as this one. I was lucky enough to have the wherewithal today to do just that. And that's why I'm here as a victor."
Nadal's last grand slam match before today was the shock loss to Lukas Rosol in the second round of Wimbledon, and if they both win their next matches then they will meet in the third round.
There were much less eventful starts for France's two main hopes, with Jo-Wilfried Tsonga beating Slovenia's Aljaz Bedene 6-2 6-2 6-3 while Richard Gasquet defeated Sergiy Stakhovsky 6-1 6-4 6-3.
It was a relatively good day for the seeds, with John Isner, Marin Cilic, Kei Nishikori, Julien Benneteau, Fabio Fognini and Tommy Robredo all winning but Marcel Granollers and Juan Monaco both fell in five-setters, the latter from two sets up.
Meanwhile, there was a first grand slam win for 18-year-old Australian wild card Nick Kyrgios, who defeated 34-year-old Radek Stepanek in three tie-breaks.