A pumped up Maria Sharapova overcame Victoria Azarenka of Belarus 6-7, 6-4, 6-2 to advance to the third round of the LA Championships on Wednesday.
World number one and top seed Dinara Safina also moved ahead with a clinical 6-2, 6-4 victory over Slovakia's Daniela Hantuchova.
"I loved it," Sharapova told reporters. "Going into the match I knew I would have to dig deep and find ways to win and hang tough."
After 20-year-old Azarenka sealed the first set tiebreaker 7-4 with a gutsy forehand passing shot, Sharapova varied her attack to deny the fleet Belarussian a chance to dictate terms inside the baseline.
The Russian three-time grand slam champion took the second set with a service winner and then cruised to victory after taking two early breaks in the third.
"I don't do anything well today," Azarenka said. I can't feel good about anything. Everything was on the top of the net or a little bit out."
Sharapova faces Alona Bondarenko in the third round on Thursday, the Ukrainian world number 33 accounting for Czech Lucie Safarova 5-7, 6-4, 7-5.
Defending champion Safina beat Hantuchova for the fourth time in seven meetings to advance to the third round and become the first to qualify for the season-ending WTA championships in Qatar.
"We play the same way, so it depends on who's going to take charge of the points, and I think at the crucial times I was more aggressive today," said Safina, who faces 14th seed Zheng Jie of China in the third round.
Fifth seed Nadia Petrova of Russia also advanced with a 6-4, 2-6, 6-3 win over Israel's Shahar Peer, while eighth seed Agnieszka Radwanska of Poland steamrolled Ai Sugiyama 6-2, 6-1.