Roger Federer was two points from an embarrassing exit from the Monte Carlo Masters on Wednesday before rallying to beat Spanish qualifier Ruben Ramirez Hidalgo 6-1, 3-6, 7-6 to reach the third round.
The world number one, who failed to retain his Australian Open crown earlier this year, was 5-4 and 30-15 down in the third set before his opponent, ranked 137th by the ATP, crumbled under the pressure.
Federer had already recovered from being 5-1 down after a string of unforced errors brought him to the brink of defeat.
He eventually won the tiebreak 7-1, wrapping it up after two hours and three minutes on his first match point when Ramirez Hidalgo sent a forehand wide.
Second-seeded claycourt king Rafael Nadal, bidding for a fourth consecutive title in the principality, never let Mario Ancic into their match, powering to a 6-0, 6-3 win over the Croatian in 75 minutes.
The muscular Spaniard won the first eight games before dropping serve but Nadal won the last three games for a routine victory.
He next faces compatriot Juan Carlos Ferrero, who beat Finn Jarkko Nieminen 6-3, 6-3, while Federer meets Frenchman Gael Monfils, who beat Croatia's Ivo Karlovic 7-6, 6-1.
"I felt a bit slow out there. He played so badly in the first set that he almost faked me out," Federer told reporters. "But when he served for the match it became tough on him."
"I'm disappointed by the way I played but tomorrow is a new match, a new day, a new opponent. And so far, it's six matches and six wins on clay so I'm happy."
FERRER VICTORY
There was no scare for Spanish fifth seed David Ferrer, who eased past former world number one Marat Safin 6-2, 6-3 to set up a third-round encounter with Serb Janko Tipsarevic, a 5-7, 7-6, 6-4 winner over Ecuador's Nicolas Lapentti.
Safin's compatriot Nikolay Davydenko, seeded fourth, held off a late challenge by Italian Simone Bolelli to go through with a 6-2, 7-6 win.
"I practiced for two hours yesterday and I was OK," said Davydenko, who retired from last week's Estoril Open final against Federer with a leg injury.
"I have a physiotherapist who is giving me treatment here. My legs are okay."
Davydenko will take on German Philipp Kohlschreiber, who beat his compatriot Nicolas Kiefer 6-2, 6-4.
On centre court, Federer started brightly, hitting 14 winners to take a one-sided first set in 31 minutes.
But Ramirez Hidalgo broke in the second game of the second set and opened up a 3-0 lead.
A nervous Federer then shrugged off two more break points but made 23 unforced errors and was trapped into a decider.
The Swiss dropped serve in the first game when he netted an easy volley and was 4-0 down after his opponent converted the second of his three break points.
Ramirez Hidalgo was caught out by the pressure and Federer rolled on despite having made 55 unforced errors.
Federer, a 12-times Grand Slam winner who has not had a coach since splitting with Tony Roche last May, has hired Spaniard Jose Higueras to improve his claycourt game.
Russia's Igor Andreev and Nicolas Almagro of Spain will meet in the third round after they benefited from the retirements of their opponents, respectively eighth-seeded Russian Mikhail Youzhny and Argentine 11th seed Juan Monaco.
