SAN JOSE, CA, USA - Two-time major champion Victoria Azarenka battled into the second round of the inaugural Mudabala Silicon Valley Classic on Monday, defeating fellow mom Kateryna Bondarenko, 6-3, 6-7(7), 7-5.

"It's a really challenging time for me and my game right now," she told Andrew Krasny during the on-court interview. "You can see with my game, there's a lot of ups and downs. The important thing is that I'm here, I'm fighting hard, and I try to do my best. That's all I can ask of myself, but it's not easy. Everyone expects to have results right away - I do too! - but I need to be patient, and keep working hard."

Playing her first hardcourt tournament since the Miami Open in March, the former World No.1 was a heavy favorite against Bondarenko, whom she'd never lost to in four previous encounters, but was made to battle as the Ukrainian saved three match points before ultimately securing victory after two hours and forty minutes on court.

Bondarenko had been ranked as high as World No.29 - winning the doubles at the 2008 Australian Open with sister Alona - before marrying and giving birth to daughter Karin in 2013. Off the tour for over a year, the Ukrainian veteran began to rise back up the WTA rankings in 2015, qualifying for that year's US Open and matching her career-best result when she made the third round of the 2016 Australian Open. She won her first title in over nine years last fall at the Tashkent Open.

Azarenka began their Stadium Court clash in glittering form, winning the first four games before Bondarenko found her footing, narrowing the deficit to just won break before the Belarusian pulled away again to capture the opening set. Bondarenko had never won more that two games in seven previous sets against Azarenka, but turned the tables in shocking fashion on Monday as she raced out to a 5-2 lead in the second.

"I should have probably played better at the end of the second set. I didn't get the momentum going until 5-2 down, and I started to play well, but I didn't take my chances and let her play into the game. But she fought hard, got a lot of balls in, and played aggressively on important points. Here we are!"

Azarenka rolled through the next four games and even held a pair of match points at 6-5, but Bondarenko refused to fold as she forced a tie-break.

Saving two set points, Azarenka engineered a third match point only to see Bondarenko turn up the heat on the backhand side to level the match, and rode that momentum into an early break advantage in the decider.

Azarenka swiftly restored order and held on for dear life, rallying from within two points of defeat and breaking the Bondarenko serve one last time to ultimately advance on her fourth match point.

In all, the Belarusian overcame 12 double faults and 50 unforced errors with 31 winners and a superior break point conversion rate, winning seven of 16 opportunities to Bondarenko's four of seven.

Up next for Azarenka is a highly-anticipated second round clash with top seed and former World No.1 Garbiñe Muguruza. The pair have played just once before at the 2016 Miami Open, which Azarenka won en route to her Sunshine Double.

"She's a great player, she's improved a lot in the last few years, winning two Grand Slams," Azarenka told reporters afterwards. "She sometimes can play unbelievable and sometimes really not. I remember our match in Miami, and it was really high quality tennis, it was a tough battle - we'll see what happens."