Patience paid off for Rafael Nadal.

It was Nadal's mental resilience, not his intimidating topspin forehand, that helped the top-ranked Spaniard overcome a difficult injury layoff and get off to an impressive start to his season on clay.

Nadal will be playing in the Madrid Open this week trying to add to his titles in Monte Carlo and Barcelona, and stay on track for yet another French Open title.

"I was patient and had the right attitude to try to get to the clay season as fit as possible," Nadal said. "Coming into the clay season having played only four matches is not the ideal preparation, but to be honest, I feel that I've been playing well."

Nadal was out of action earlier for a couple of months earlier this year because of a lingering right hip injury that forced him to retire in the Australian Open quarterfinals and kept him from playing in Indian Wells, Miami and Acapulco.

"They were difficult times. I feel like I've missed a lot of important opportunities in my career (because of injuries). I counted all the majors in which I was not able to compete in normal conditions and there were a lot," Nadal said. "They are unpleasant times. To make it through it, you have to be patient."

Nadal returned to action in the Davis Cup quarterfinals to help Spain defeat Germany, then went on to win in his 11th Monte Carlo title and 11th Barcelona title.

"If my body keeps responding well and I win matches, I think I'm ready," he said.

Nadal has been winning with ease since returning to the courts.

He was never really challenged in Monte Carlo or Barcelona, and arrives in Madrid carrying a winning streak of 46 straight sets on clay.

The 16-time Grand Slam champion has won 36 of his last 37 matches on the surface, including 19 straight. His last loss on the dirt came against Dominic Thiem in Rome last year.

Nadal, who will be trying to win his 11th French Open title in a few weeks, won his 400th clay-court match in the semifinals at Barcelona. He has won 16 of his 17 matches this year in all surfaces, including two on clay in the Davis Cup.

His biggest challengers in Madrid will be third-ranked Alexander Zverev, fifth-ranked Grigor Dimitrov and seventh-ranked Thiem, who lost to Nadal in last year's final in the Spanish capital. Nadal defeated Dimitrov in the semifinals in Monte Carlo and beat Zverev in straight sets in the Davis Cup quarterfinals.

Novak Djokovic, last year's semifinalist in Madrid, will be trying to get his season going after nursing a lingering right elbow injury. The 12th-ranked Serb hasn't made it past the last 16 in five tournaments this year. He lost in the third round in Monte Carlo and in the second round in both Miami and Indian Wells. He failed to advance past the last 16 at the Australian Open.

Djokovic didn't catch a break with the draw in Madrid, having to face Kei Nishikori, the Monte Carlo finalist.