Novak Djokovic got the type of win he needed to boost his confidence and get his game back on track.
He beat 20th-ranked Kei Nishikori 7-5, 6-4 in the first round of the Madrid Open on Monday, his highest-ranked win in 10 months.
Djokovic broke serve late in each set to get past Nishikori after nearly two hours in the Magic Box.
"I'm glad that match went my way, but it could have gone his way as well. I managed to play the right shots in the important moments," Djokovic said. "It was exactly what I needed for my confidence and for my game. I'm just happy to go through this one."
Coming back from a right elbow injury, Djokovic hasn't made it to the quarterfinals in his previous five tournaments this year, admitting he returned to tennis too quickly. In his last event, he lost in the third round in Monte Carlo, where Nishikori reached the final.
"I'm just trying to take one day at a time, build my game, because that's something that I feel is a priority right now," Djokovic said.
"I was looking forward to these kind of matches, looking to try to win these kind of matches. I couldn't ask for a better start. I feel much better about everything that is happening on the court and around tennis, in general, with my body than maybe two months ago."
Djokovic was aggressive from the start, hitting 26 winners against Nishikori, who has made at least the Madrid quarterfinals for the last five years. He was a finalist in 2014, losing to Rafael Nadal.
Top-ranked Nadal will make his tournament debut against Gael Monfils, who defeated qualifier Nikoloz Basilashvili 6-2, 3-6, 6-3.
Maria Sharapova, who won in Madrid in 2014, made it to the last 16 by defeating Irina-Camelia Begu 7-5, 6-1 in only her second match since the Australian Open. She has been dealing with a left forearm injury.
"It was a lot of hard work," Sharapova said of her match. "Being down a break to start off both of those sets didn't make things easy for me. That will certainly help me moving forward."
Australian Open champion Caroline Wozniacki edged past Ashleigh Barty 6-2, 4-6, 6-4. Wozniacki reached the 2009 final on debut and hasn't been close since.
"I was lucky to get away with it in that third set," the second-seeded Wozniacki said.
Sloane Stephens cruised past Samantha Stosur 6-1, 6-3 in a matchup of U.S. Open champions.
Milos Raonic defeated Nicolas Kicker 6-3, 6-2 to set up a second-round encounter with third-seeded Grigor Dimitrov, while Richard Gasquet beat Tomas Berdych 6-4, 6-2 to advance to play qualifier Dusan Lajovic, who got past Karen Khachanov 6-3, 6-2.
In a first-round match between Frenchmen, Benoit Paire hit 39 winners to defeat 18th-ranked Lucas Pouille 6-2, 6-3, advancing to face 19-year-old Denis Shapovalov of Canada, who got past Tennys Sandgren of the U.S. 6-1, 6-4.
Veteran Feliciano Lopez defeated Spanish countryman Pablo Andujar 7-6 (4), 6-3.