World number one Rafael Nadal laboured into the third round of the Monte Carlo Masters while Roger Federer had a smooth start to his campaign on Wednesday.
The easy-looking 6-2, 6-3 scoreline against Argentine Juan Ignacio Chela masked a rusty performance by the Spaniard, who looked a lot less relaxed than his Swiss rival, a 6-4, 6-4 winner against Italian Andreas Seppi.
Nadal, who is gunning for a fifth successive title, a record in the professional era, looked sloppy at times but regained composure when it mattered to wrap up the win after 86 minutes.
"I played some games well. I played some terrible games. Up and down all the match," Nadal told a news conference.
"But I think it was a comfortable win. I was never scared of losing. Sometimes, things like this happen. I will try and not repeat these mistakes in the next match."
Nadal, who has now won his last 23 matches in Monte Carlo, will next take on Ecuador's Nicolas Lapentti, who saved three match points in a 7-6, 2-6, 7-6 win over Marat Safin.
The Russian former world number one, who was 5-2 up in the third set, eventually lost his temper and despite staving off five match points, bowed out as he lost the third-set tiebreak 8-6 after three hours and 29 minutes.
The match was held up for 10 minutes after a spectator collapsed in the stands and had to be evacuated by first-aid workers.
Argentine Juan Martin Del Potro became the highest seeded casualty when he went down 4-6, 6-1, 6-4 to Croat Ivan Ljubicic following a stop-start performance.
Ljubicic, who served 14 aces against the fifth seed, will face Italian Simone Bolelli on Thursday.
Federer, who could face Nadal for a fourth consecutive final at the Monte Carlo Country Club appeared very relaxed on a sun-drenched centre court, clinching victory on his fourth match point after a final burst from Seppi.
He will next face compatriot Stanislas Wawrinka for a quarter-final spot after the 13th seed beat Argentine Martin Vassallo Arguello 2-6, 7-5, 6-2.
"I thought I played okay. I had a good stretch at the end of the first set, beginning of the second," Federer told reporters.
"Maybe I could have made it easier for myself in the second. I had some opportunities. He hung in there and I didn't play my best. But still happy I came through so good."
Federer, who married his longtime girlfriend Mirka Vavrinec last weekend, broke in the ninth game and took the opening set with a backhand winner down the line.
The Swiss dismissed a break point in the second set with an angled serve which Seppi returned wide and another long return gave Federer his fifth victory in as many matches against the Italian.
Nadal, who was next on centre court, was not as cool as Federer.
The four-times French Open champion missed several easy shots, including a routine smash at the net that allowed Chela to break back in the second set.
The Spaniard shrugged off a break point at 5-3 in the second set before prevailing on his first match point.
Eighth seed Nikolay Davydenko of Russia also progressed with a 6-4, 6-3 win over Croat Ivo Karlovic and will face Argentine David Nalbandian, who recovered from a set and a break down to beat Spaniard Marcel Granollers 4-6, 6-3, 6-1.
Italian qualifier Fabio Fognini set up a third-round meeting with Briton Andy Murray after demolishing Croatian 14th seed Marin Cilic 6-2, 6-0.
