INDIAN WELLS, CA, USA - No.8 seed Angelique Kerber fought through her toughest test of the fortnight so far, coming back from a set down against qualifier Natalia Vikhlyantseva to reach the fourth round at the BNP Paribas Open, 3-6, 6-1, 6-1.

Kerber, a two-time semifinalist here in Indian Wells, cruised through her opening match in the last round against Yulia Putintseva, striking 29 winners and just 12 unforced errors en route to a quick 6-0, 6-2 victory. But it was a completely different story in the third round against Russian 22-year-old Vikhlyantseva.

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“[Matches like this] give me again confidence that I can turn around matches; that I can play also three sets; also in the close moments that I'm there, that I can trust myself,” Kerber told press after the match.

“I think that I had now, like, two completely different matches. One really good one from the beginning until the end, and now today with few up and downs. I think it's good also when I'm looking ahead to the next round.”

One of five qualifiers to reach the third round at Indian Wells this year - the most to do so since 2004 - Vikhlyantseva was dialed in from the start against Kerber. She had already fought through four matches in a row, winning all eight sets - including a big upset over No.24 seed Carla Suarez Navarro in the second round.

She took the initiative early on against Kerber, who came out sluggish at the start on a cloudy, cool Monday in the Coachella Valley. After going down an early break. Vikhlyantseva turned around a 0-2 deficit and reeled off four games in a row to make it 4-2. She edged through to claim the opening set 6-3.

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But Kerber responded like a three-time Grand Slam champion, reeling off five games in a row in the second set to record a double-break and force the match into a decider.

“I think the key was in the second set, that I turn around and that I came back after the first set,” Kerber said. “It's never easy to play against someone [for the first time]. You don't know how she's playing. I mean, you can talk a lot, but when you are on court it's always different.

“I think that I need a little bit time to adjust and, yeah, feeling also my rhythm, because the conditions out there today are completely different from two days ago when I was playing.”

Back into the fourth round at Indian Wells for the fifth time, Kerber will take on an in-form No.9 seed Aryna Sabalenka, who edged past No.24 seed Lesia Tsurenko, 6-2, 7-5.

“I think it's the same situation. I never played against her,” Kerber said. “I mean, yeah, she had a lot of confidence. She played very well in the last few months. She is going for it. She is hitting the ball as well really fast, and she is trying to dominate the game.

“I know a little bit about her, but it's the same. It will be a new match. We are starting from zero, both, and I will try to play like I finished the match today.”