Rafael Nadal returned from an injury layoff to beat Miomir Kecmanovic 6-1 7-6(4) on Wednesday and reach the last 16 in the Madrid Open claycourt tournament.
Nadal, competing in his first match since March following a rib injury, quickly found his rhythm in a strong start against Serbian Kecmanovic.
Rain suspended play early in the second set and 21-times Grand Slam champion Nadal lost momentum.
The 35-year-old Spaniard, hitting with explosive power, recovered from failing to serve out the match at 6-5 in the second set to seal victory in just under two hours.
"Every comeback is different," Nadal told reporters.
"We had to put all circumstances together to analyse every single comeback, and today has been a very important match for me, playing at home on clay against a player that has been playing well for the past couple of months.
"So (if you) put everything together (it is) a very tough first round. I think I managed it very well... I just try to stay humble to know things (are) not going to be perfect here and just moving forward with the right determination, to accept that I need to fight, I need to stay positive."
Nadal, who improved his win-loss record to 21-1 for the season, is aiming to win his sixth title on home soil in Madrid having last won the tournament in 2017, and will next play qualifier David Goffin.
Earlier, world number three Alexander Zverev overcame a slow start to beat Marin Cilic 4-6 6-4 6-4, while qualifier Dusan Lajovic beat fifth seed, Casper Ruud, 7-6(7) 2-6 6-4.
Greece's Stefanos Tsitsipas cruised into the next round after a 6-3 6-4 win over France's Lucas Pouille.
In the women's draw, Tunisian Ons Jabeur reached her second WTA 1000 semi-final after beating former world number one Simona Halep 6-3 6-2.
Jabeur won 77.8% points on her first serve and converted four of five break points against twice champion Halep to seal victory in just over an hour.
World number 10 Jabeur will face qualifier Ekaterina Alexandrova for a spot in her first WTA 1000 final after Alexandrova defeated Amanda Anisimova 6-4 6-3.
Swiss Jil Teichmann beat Ukraine's Anhelina Kalinina 6-3 6-4 and will face American Jessica Pegula after she beat Spain's Sara Sorribes Tormo 6-4 6-2.