Australian Open Women's Quarter-Final Tips: Underdogs capable of continuing the upsets

• Rybakina now Betfair Exchange tournament favourite

• Linette with decent underdog's chance

• Vekic also capable of a shock

Rybakina's serve too solid for Ostapenko

Straight sets were the order of the day with Elena Rybakina getting the better of Jelena Ostapenko and Victoria Azarenka defeating Jessica Pegula. I mentioned yesterday that Ostapenko would need to win mid-60s percent of service points to have a chance, but she only managed 55% - it was Rybakina who won 66% of service points in the match.

Linette capable of competing with Pliskova

Starting off the Wednesday schedule is Karolina Pliskova versus Magda Linette, and it's Pliskova who is 1.654/6 to progress - similar to her line in the Billie Jean King Cup in November, when Linette took the win in straight sets. However, historically, Pliskova has had the edge over the Pole, winning seven of their nine career meetings.

Numbers-wise, there's not much to split the duo. Pliskova's previously dominant serve isn't quite at the level it once was, and while opposition quality has something to do with the data as well, it's evident that Linette has a decent underdog's chance to make her first Slam semi-finals.

Interestingly, despite there not being that much between the duo in the match pricing, Linette is 34.033/1 in the outright market and Pliskova far shorter at 13.525/2 - so if you are of the mindset that Linette looks like some value here, focusing on trading the outright market could well be the better option.

Vekic capable of another win over Sabalenka

Despite winning five of her six matches against Aryna Sabalenka, Donna Vekic is a heavy underdog at 4.30100/30 for the second quarter-final tomorrow.

This head-to-head record included a win for the Croatian player in three sets on hard court in San Diego in October, so it's clear that Vekic will be no pushover here.

In addition, data between the duo doesn't imply that the market line makes sense here, and I can't help that there's been an over-reaction to Sabalenka winning her last eight matches in straight sets. Only on two occasions of those eight has her opposition been top 20 though, and she's not faced top 10 opponents at all in that sample size either, so effectively she's won most of those matches in straight sets when a heavy market favourite. Of course, it's a positive for her to have done so, but it's dangerous to over-react.

Having said that, Sabalenka's serve data this year so far has been outstanding - holding at around 90% - but Vekic has more impressive return data in 2023 so again, there's not much to demonstrate that Sabalenka should be so short-priced. I'm going for a big upset here.