SAN JOSE, CA, USA - Former champion Victoria Azarenka weathered a late wobble against qualifier Harmony Tan, but secured a straight sets victory in her Mubadala Silicon Valley Classic opening match. 

After dominating the Frenchwoman's service games for a set and a half, Azarenka found herself in trouble as Tan rallied back. But she righted the ship just in time to seal the victory, 6-2, 6-4 in an hour and 17 minutes. 

Read more: 'I needed to get mean': Vekic dispatches Doi, finds her way in San Jose

“I felt that it wasn’t going to be easy,” Azarenka told after the match. “First rounds are obviously not easy, and I haven’t played in a while so I had to get used to the conditions. That was important.

“There were moments where I thought I played really well, and there were moments where I lost that concentration a little bit. But a win is a win, and I have to move forward from here.” 

Azarenka, who lifted the trophy here in 2010, made a strong start fighting ahead to a double-break, 3-0 lead. It kept her ahead as Tan surged back, forcing four consecutive breaks of serve, 5-2. 

After closing out the opening set, Azarenka surged to another double-break, 3-0 lead. But with the set - and the match - looking well within her grasp, Azarenka faced a late wobble as Tan once again found her rhythm. The Frenchwoman turned around the 0-3 deficit, reeling off four games in a row to take her first lead of the match, 4-3.

But Azarenka found some first serves in order to level the score a game later, and a late break at 5-4 proved to be decisive as the Belarusian served out the victory in an hour and 17 minutes.

Up next, Azarenka will face No.5 seed Donna Vekic in the second round. Vekic fought past Misaki Doi 6-4, 3-6, 6-4 earlier in the day to advance. 

“I don’t think we’ve played before,” Azarenka said. “I know she’s a dangerous player. She’s very talented and she has a lot of good shots. It will be interesting to see how I can deal with it.”

In photos: Hitting the hard courts: The best photos from San Jose and Washington DC

But before she can hit the court against Vekic on Thursday, Azarenka will celebrate her 31st birthday tomorrow, July 31. Or will she?

“I don’t plan my birthday, so we’ll see what happens,” she said.