Spanish world No. 1 Rafael Nadal beat the Czech Republic's Radek Stepanek 2-6, 6-4, 7-5 in his opening match at the BNP Paribas Open in Indian Wells, California.
"Tough one. Anything can happen, but in the end I played well," Nadal said.
The 35-year-old Stepanek forced the defending champion to dig in and step up his game in the second set.
"I'm happy to be through, because the start of the match, even if I felt at the beginning I didn't play that bad, it was very quick 4-1 (for Stepanek), and I felt I was not playing that bad," the 27-year-old Nadal said.
The Spaniard appeared hesitant and unfocused in the first set before a huge Court 1 crowd in Indian Wells.
Nadal stepped up his game and attacked Stepanek in the second set, forcing the Czech ATP Tour veteran to go on defense.
The Spaniard, who had a 6-0 career record against Stepanek going into the match, had to grind out the third set, getting a break late in the match and serving it out.
In other men's action, Switzerland's Stanislas Wawrinka defeated Croatia's Ivo Karlovic 6-3, 7-5, while Britain's Andy Murray beat the Czech Republic's Lukas Rosol 4-6, 6-3, 6-2.
Switzerland's Roger Federer defeated France's Paul-Henri Mathieu 6-2, 7-6 (7-5).
The BNP Paribas Open is one of nine ATP World Tour Masters 1000 events, which are among the biggest tournaments on the men's tennis calendar.
On the women's side, Russia's Alisa Kleybanova beat Spain's Garbine Muguruza 6-3, 6-2, while fellow Russian Maria Sharapova defeated Germany's Julia Goerges 6-1, 6-4.
The Czech Republic's Karolina Pliskova defeated countrywoman Klara Zakopalova 7-5, 6-2 and China's Li Na, the top seed, beat countrywoman Zheng Jie 6-1, 7-5. EFE