Novak Djokovic beat Kei Nishikori at the Madrid Open to get the type of win he needed to boost his confidence and get his game back on track.
Serbian 10th seed Djokovic defeated the 20th-ranked Nishikori 7-5 6-4 in the first round.
Djokovic broke serve late in each set to get past Nishikori after nearly two hours.
"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 quarter- finals in his 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.
Top-ranked Rafael Nadal will make his tournament debut against Gael Monfils, who defeated qualifier Nikoloz Basilashvili 6-2 3-6 6-3.
Milos Raonic defeated Nicolas Kicker 6-3 6-2 to set up a second-round encounter with third-seeded Grigor Dimitrov.
Qualifier Dusan Lajovic got past Karen Khachanov 6-3 6-2 to set up a second- round meeting with Frenchman Richard Gasquet.
In a first-round all French affair, Benoit Paire hit 39 winners to defeat 15th- seeded Lucas Pouille 6-2 6-3 and progress to a clash with 19-year-old Canadian Denis Shapovalov.
Veteran Feliciano Lopez defeated Spanish countryman Pablo Andujar 7-6 (7-4) 6-3 while Argentine 13th seed Diego Schwartzman, Damir Dzumhur, Federico Delbonis and Mikhail Kukushkin also won on Monday.
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