Defending champion Rafael Nadal survived a serious scare against Radek Stepanek before reaching the third round of the BNP Paribas Open in Indian Wells.
Stepanek came out firing and dominated the first set but Nadal rallied to level and overcame another big scare in the third to pull out a 2-6 6-3 7-5 victory.
The Spaniard, who next meets another quirky player in Alexandr Dolgopolov, revealed the back injury that severely hampered him in the Australian Open final is still on his mind, with eight double faults showing all is not well.
Nadal said: "I was a little bit scared for the back. I am not feeling yet 100 per cent confident with my serve.
"He is not the right player to play against in the first match because what you want to find is rhythm and against him every point is different."
Roger Federer extended his winning run with a 6-2 7-6 (7-5) victory over Paul-Henri Mathieu.
The Swiss came into the tournament as the form player on the men's side after winning the high-profile tournament in Dubai last week.
Federer's countryman Stanislas Wawrinka looked to have a difficult outing against 6ft 10in Ivo Karlovic for his first regular tour match since beating Nadal to win the Australian Open in January, but the third seed avoided any drama in a 6-3 7-5 win.
He said: "I'm just feeling great and happy to be back, especially here. It's an amazing tournament.
"I was a little bit scared about the way I was going to play. But after five or six days on the practice court with (coach) Magnus (Norman), I was feeling really good. I'm really happy with my level. I really think I'm playing great tennis."
But Lleyton Hewitt will have to wait a little longer for his 600th win after losing 7-6 6-4 to in-form 17th seed Kevin Anderson.