(Add Murray victory, quotes, details)
By Gregory Blachier
MONTE CARLO, April 17 (Reuters) - Novak Djokovic's gamble on his injured ankle at the Monte Carlo Masters appeared to be backfiring before he dug in to battle past Russian Mikhail Youzhny 4-6 6-1 6-4 in the second round on Wednesday.
While Djokovic grimaced and growled through the pain barrier to fight back from 0-4 down in the opening set, Rafa Nadal was all smiles after launching his bid for a ninth consecutive Monte Carlo crown with a ruthless 6-1 6-2 win over Australian Marinko Matosevic.
World number one Djokovic, who sprained his ankle on Davis Cup duty 10 days ago, made a late call to participate in the tournament in his adopted home town and was relieved to have survived his first match on clay this season.
"I'm not 100 percent because of my physical issue but I'm still in the draw. I live here. Everything's alright," Djokovic said in a courtside interview.
During a training session on Tuesday, Djokovic avoided putting too much pressure on his ankle but he did not have that luxury as Youzhny made him chase the ball around the court.
Once Djokovic levelled at 4-4, he relied on his greater weight of shot to see him through even though he twisted his ankle again during the second set.
"(It was painful) for the next 15 minutes, then it kind of faded away because I had a good protection ... I am happy to win because I'm happy to compete," Djokovic told reporters.
Following an exchange of breaks in the third set, he broke decisively in the ninth game and sent Youzhny packing with an ace on match point.
The Serbian will next take on 14th-seed Juan Monaco who took full advantage of Ernests Gulbis's third-set meltdown to win 6-0 3-6 6-3.
The Latvian was penalised a game for smashing his racket against the umpire's chair following a point penalty for kicking the ball.
Third seed Nadal returned from a month-long break to record his 43rd successive victory in the principality.
The Spaniard, who missed seven months last year due to knee problems, was loudly cheered by the packed crowd.
Matosevic opened a 2-0 lead in the second set but Nadal reeled off the next six games to advance to a meeting with 16th seed Philipp Kohlschreiber of Germany.
"I played well at the beginning, with the right intensity, with no mistakes. I was trying to do the right things to find a good feeling on the ball, to find the right rhythm. And I think I did," Nadal told a news conference.
"I played to the right places, and that gave me confidence."
The world number five announced his comeback by winning three of his first four tournaments, including the Indian Wells Masters Series, and is favourite to continue his reign on the picturesque Centre Court that has been his stage since he first won the tournament in 2005.
World number two Andy Murray also enjoyed a solid start by beating qualifier Edouard Roger-Vasselin of France 6-1 6-4.
"It takes time (to adapt). It doesn't matter how much training you do, until you get the matches and the feel of how to play under pressure, it's completely different," said the Briton who next faces Swiss Stanislas Wawrinka.
Fourth seed Tomas Berdych had to recover from a break down in each set to move past Spaniard Marcel Granollers 7-5 6-4.
Canadian 12th seed Milos Raonic failed to set up a big-serving clash with Juan Martin Del Potro when he lost to Finland's Jarkko Nieminen 6-3 1-6 7-6.