The Swiss world number 13 looked a class above the Russian lucky loser as she dominated the baseline rallies and romped to a 6-3 2-0 lead at the warm-up tournament for the Australian Open.

Kalinskaya hit back with two breaks of her own, however, and would have had a third for a 4-3 lead if Bencic had not successfully challenged a line call and then battled back from 40-0 down to hold.

Another break on a Kalinskaya double fault gave Bencic the chance to serve for the match and she made no mistake to set up a last-eight meeting with top seed Caroline Garcia.

"I thought it was a really solid match," said Bencic. "I think I lost my focus there for a bit in the second set but I was able to regroup and close it out in two sets.

"I'm really trying to get more consistent, I feel like my game is there but sometimes I turn up to a game and I'm completely off."

Former French Open champion Petra Kvitova (32) also advanced to the last eight when China's Zheng Qinwen (20), who had twice served for the opening set, withdrew after losing it in a tie break.

American Danielle Collins (29), runner-up to Ash Barty at the Melbourne Park Grand Slam last year, continued her fine form in the lead-up to this year's tournament with a 6-3 7-6(2) victory over Jil Teichmann.

France's Garcia, the top remaining seed, earned a hard-fought 6-3 3-6 7-5 victory over Katerina Siniakova to reach the quarter-finals on Wednesday.

Garcia made a promising start under the lights and looked comfortable in the opening start before Siniakova mounted a challenge by bouncing back in the second set.

The third set remained level pegging until Garcia was able to make the breakthrough and wrap up the match in just over two hours, surviving a tremendous fight from her Czech opponent.

The match was Garcia's first of the tournament after she was handed a bye in the first round and the contest ended close to midnight.

"I had to wait a very long time to start so it was very difficult, and she (Siniakova) played some unbelievable tennis which caused me a lot of issues," Garcia said in her on-court interview.

Asked how she was able to turn things in her favour in the end, Garcia said: "In the last couple of games, I was able to be more solid and bring back more returns, same as the first set.

"I was a little bit aggressive on few shots and tried to be closer to my baseline."