Victoria Azarenka admits she must learn to curb her emotions after rounding on the umpire during her victory over Nadia Petrova.

Azarenka had already won the opening set on a tie-break when she lost her discipline.

Unhappy with a line call, the 19-year-old from Belarus accused the umpire of "ruining the game" before going over to sarcastically shake the hand of the line judge.

Azarenka's tantrum occurred at 4-2 down in the second set as she struggled to get on top of Petrova's game. She went on to lose the set 6-2.

But the number eight seed intends to work on curbing her temper after admitting she felt bad about losing her cool with the official.

"I didn't apologise but I actually felt pretty bad because I reacted pretty bad for that," said Azarenka.

"But sometimes it is really tough to control your emotions when the match is really tight and some bad call comes up.

"I just really have to learn how to do it. I've always been an emotional player and I'm always going to be. I just need maybe not to go crazy on my emotions when I am pumped up.

"I just have to keep trying to calm myself down sometimes. But it is not like sitting in the living room and watching TV. You are playing 35 degrees Celsius, it is hot and you're playing a close match, so it is tough."

In a one-sided final set on Court Three, Azarenka's class told and she closed the match out to win 7-6 (7-5) 2-6 6-3.

Azarenka will face Serena Williams tomorrow in the quarter-finals.

She posted a victory over the number two seed at the Sony Ericsson Open in Miami earlier this year, beating Williams in the final to secure her third WTA Tour singles title.

Although Williams was nursing a leg injury in that match, Azarenka ran out victorious by a 6-3 6-1 margin.

"The Miami final is tough to take something out of because she was injured there," said Azarenka.

"Here it is a completely different game and surface. I just have to try to maybe stick to the same plan as I played in Miami and just to fight for every point."