Monte Carlo - Rafael Nadal seems determined to play the most punishing clay schedule possible, with the top seed at the Monte Carlo Masters insisting he still intends to compete for four of the five weeks heading into the French Open.

"You never know, no? You never know," said the four-time champion on Monday. "(It) always depends of the results. But, my normal schedule is these four. But you never know what's going on."

Nadal's big job starts this week in the principality, where the top seed and world number 1 will bid for a fifth straight trophy at the iconic venue. In addition, Nadal is due to compete on his favoured clay in Barcelona next week followed by the Rome Masters.

After a week off he will play the new Madrid Masters, which has to be considered a question mark due to the city's location 650 metres above sea level, a fact which makes a huge contrast with sea-level conditions at Roland Garros starting May 24.

Nadal learned the identity of his opening opponent after a bye as Argentine Juan Chela beat Igor Kunitsyn of Russia 6-4, 2-6, 7-5 to take a place across from Nadal.

Two Spaniards reached the second round as Oscar Hernandez beat Frenchman Julien Benneteau 6-4, 6-4 and Marcello Granollers stopped Argentine Jose Acasuso 7-6 (7-4), 7-6 (7-2).

Nadal said that while he sent his personal congratulations to rival Roger Federer a few weeks ago in Miami when the Swiss number 2 announced that he will become a father in the summer, his rival's marriage over the weekend also took Nadal somewhat by surprise.

The 22-year-old Spaniard added with a straight face: "I am thinking about that, be married and be father right now for the next years," he said before breaking into a smile at his own joke.

Nadal trails Andy Murray with two trophies to three for the surging Scot this season.

Murray comes to the clay season having beaten Novak Djokovic easily for the Miami title eight days ago and full of confidence.

He is especially keen to improve on clay, where he has never reached a quarter-final. "I enjoy clay, it's challenging. It's nice to have goals where it's not just about winning events.

"I'm hitting the ball fine but it takes time to get used to movement," said the fourth seed. "I haven't hit a ball on clay since the French last year so it has been 10 or 11 months.

"I'm just getting used to sliding, not being 100 per-cent sure under your feet takes a bit of time."