INDIAN WELLS, CA, USA - Two-time BNP Paribas Open semifinalist Karolina Pliskova reached a fifth straight fourth at the Indian Wells Tennis Garden, knocking out a surging Ysaline Bonaventure, 6-3, 6-2.

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"I think I was solid today," Pliskova said in her post-match press conference. "For sure, it was not the best. I somehow felt strange and the match was strange. I think also playing her first time, I didn't know much what to expect, and I think she can play strange somehow."

Bonaventure had battled through qualifying and won all four matches from a set down - including an upset over No.28 seed Donna Vekic - but Pliskova, who rallied from a set down to defeat Misaki Doi in her opening round, had the answers on Monday, dispatching the Belgian after 66 minutes on Stadium 3.

"My serve was good, the match before also, now also. So I think the last four sets - if we don't count the first one which I lost against Doi - were pretty solid."

The former World No.1 has enjoyed a solid start to 2019, winning her 12th career WTA title at the Brisbane International and reaching the Australian Open semifinals. After an early exchange of four service breaks, the three-time WTA Ace Leader found her footing faster and took a 5-2 lead to start the match, clinching the opening set with a service winner.

Pliskova chatted with Conchita Martinez in the ensuing changeover - Martinez co-coaches her alongside fellow former WTA star Rennae Stubbs - and the No.5 seed took that momentum into the second set, breaking serve to open and holding on behind a flurry of aces.

"We are doing a lot of practices, a lot of stuff on the courts, even some gym. I have been here a week, so I just had enough time to do something more and to prepare. She makes me work every time, more and more," she said of Martinez. "It's good for me. So far all good."

Bonaventure showed some frustration late as the Belgian couldn't convert a game point chance in the seventh game, and Pliskova pounched for a double break and ultimately served out the match in style, striking 13 total aces.

Standing between Pliskova and a fourth BNP Paribas Open quarterfinal is No.21 seed Anett Kontaveit, who advanced after 2018 US Open semifinalist Anastasija Sevastova was forced to retire due to a viral illness in the first set.

"We played Stuttgart last year; I was playing well there. It was quite quick. I was serving well. It's going to be more about the serve, because on the serve I think I can be better, for sure, if I keep on serving like I was the last two matches.

"I think she's solid in everything, what she does. So she's good in defense. She can attack from the forehand. So I think she's fighting a lot, and it's gonna be tough.

"It's more about me, so I have to just go for it, and then I think I have a good chance to win."