Rafael Nadal's Indian Wells title defence got off to a rocky start on Saturday, as the world number one was forced to fight to a three-set victory over Radek Stepanek.
Nadal needed nearly two and a half hours to get past the talented Czech 2-6, 6-4, 7-5, with eight double faults doing little to help his cause in the second-round clash.
Meanwhile, Wimbledon champion Andy Murray, the fifth seed, fought back from a set down against another Czech, subduing Lukas Rosol 4-6, 6-3, 6-2.
The going was easier for four-time champion Roger Federer and fellow Swiss Stanislas Wawrinka, who is playing his first tournament since his Australian Open triumph.
Federer defeated France's Paul-Henri Mathieu 6-2, 7-6 (7/5) while Wawrinka, seeded third, downed Croatian Ivo Karlovic 6-3, 7-5 in just 63 minutes.
"It was a difficult match to start against Ivo," said Wawrinka. "It's never easy. He's a tough player.
"He doesn't give you so much rhythm. But I'm really happy the way I was playing, the way I was aggressive on the court, and to win in straight sets was really important for me."
Nadal said Stepanek was a similarly tough opening opponent, his unpredictability making it hard to get in a groove.
"What you want to find in the first (match) is rhythm, and against him every point is different," Nadal said.
Nadal appeared to have gained control of the contest when he won the second set with a single service break and broke again to open the third. He immediately gave the break back, however, and had to save three break points before holding in the sixth game.
"It was a tricky situation in the 0-40," said Nadal, who responded to the danger with a service winner, an ace and a backhand passing winner. "After that, I think I played better.
For Murray, early struggles at Indian Wells are nothing new. Murray reached the final on the hardcourts of the California desert in 2009, but he had lost his openers in two of the past three years.
"Today, I was a set and a break down," he said. "I got broken three times in a row at the end of the first set, beginning of the second. You know, I just kind of kept going and found a way to win, which is always the most important thing."
Colombia's Alejandro Falla came back from 2-5 down in the third set to beat 18th-seed Jerzy Janowicz of Poland 6-3, 2-6, 7-6 (7/5), saving one match point on the way.
Falla will take on Canadian Milos Raonic, who pounded 33 aces past France's Edouard Roger-Vasselin in a 7-6 (7/4), 4-6, 7-6 (7/2) victory.
In women's action top seed Li Na, who won her second Grand Slam title at the Australian Open in January, won an all-Chinese clash with Zheng Jie 6-1, 7-5.
Fourth-seeded Russian Maria Sharapova got her title defence off to a strong start with a 6-1, 6-4 victory over Germany's Julia Goerges.
"I thought I did what I had to do," said Sharapova, a former world number one who is trying to reach her first final of 2014.