MELBOURNE - Karolina Pliskova and Donna Vekic lamented the serve struggles that were their undoing in respective Australian Open quarter-final losses to Magda Linette and Aryna Sabalenka, but both took some positives from encouraging runs at Melbourne Park.

Former world number one Pliskova slipped into the second week of the tournament with little fanfare and reached her second straight Grand Slam quarter-final after her run at last year's U.S. Open.

"Super disappointed about today, because I just thought this was a match which I should win and I could win," Pliskova, who missed last year's tournament due to an arm fracture, told reporters after her 6-3 7-5 defeat on Wednesday.

"Obviously the serve was not great today at all. I suppose you can have days like this. I have been serving really well for like all my matches, and pretty much like for the last two, three weeks."

Pliskova made seven double faults compared to just one from her opponent. The Czech also chalked up 36 unforced errors, more than double Linette's count.

"On the other hand, I think I played some good tennis here," she added. "All the matches were quite good. For sure, some positive things. Just happy to be back in this stage of tournaments. I've got to keep trying."

Czech 30th seed Pliskova had come into the contest with a 7-2 record against Linette but the Pole had beaten her in straight sets in their most recent meeting at the Billie Jean King Cup at the end of 2022.

"I don't think she's much different than she was," Pliskova said. "Of course she improves, but I think the main thing ... is just a belief and the confidence, which obviously she has now.

"I think she really made it like difficult for me, not missing many balls, not giving anything for free, any mistakes.

"I just didn't play a great match. I don't think that it was bad, but definitely I can play better."

GREAT START

Croatia's Vekic was undone in part by her 13 double faults in an error-prone 6-3 6-2 loss to Sabalenka, with the Belarusian winning 75% of points against Vekic's second serve.

"It was all over the place. But I think mostly in the net," Vekic said. "My serve is one of my biggest weapons, so if that's not working, it's very tough out there."

The world number 64 was boosted by her first Grand Slam quarter-final run since the 2019 U.S. Open and is looking to replicate her form at upcoming tournaments.

"I'm sure in a couple of days I'll realize what a great month it has been, what a great start of the year," Vekic said.

"Right now I am sad, disappointed. But I think it would be strange if it wasn't like that. Most importantly, I really enjoyed my time here. It's just the beginning of the season."

(Reporting by Hritika Sharma in Bengaluru; Editing by Peter Rutherford and Christian Schmollinger )