THE four semi-finalists at the Brisbane International have been decided, with three top five players winning through to the final four on Day 5 of the tournament. Third seed Naomi Osaka, fifth seed Petra Kvitova and second seed Karolina Pliskova are all set for a huge semi-finals day, joining fellow winner, eighth seed Madison Keys in the round.

Earlier in the day, the Japanese world number three Osaka took three sets to take down the in-form Kiki Bertens, defeating the sixth seed Dutchwoman, 6-3 3-6 6-3. Despite Bertens serving a massive 12 aces, it was Osaka’s consistency – 67 per cent on her first serves, and 54 per cent returning to Bertens, that got the job done. It was a tight contest throughout and while Osaka is still returning after injuring herself at the WTA Finals – where ironically Bertens filled in for her – she has started her Australian Open title defence on the right note in the first Australian summer WTA Tour tournament.

Kvitova’s 6-4 6-2 straight sets win over giant-killing qualifier Jennifer Brady was important for the Czech’s run to the last four. Brady stunned Maria Sharapova in the first round of the tournament, then triumphed over world number one and tournament favourite, Ash Barty in the Round of 16. Kvitova proved too strong on this occasion however, not taking the American lightly and booking her spot in the semi-final. Her whopping first serve winning percentage of 93 was nothing short of elite, as the left hander produced eight aces and broke three times from eight opportunities.

The Czech will face Keys in the semi-finals after the American also secured an easy passage through to the final four, triumphing over countrywoman, Danielle Collins 6-4 6-1. After a tight first set, Keys broke three times in the second set, also winning 93 per cent of the points on her first serve, as well as 70 per cent on her second serve. She punished Collins off her serve, winning 31 return points, while Collins could not find a way to penetrate Keys, winning just six and not having a single break point opportunity.

In the final match of the day, Pliskova got over another American in Alison Riske and now takes on Osaka in a massive top three battle for a spot in the final on Sunday. In the evening clash on Pat Rafter Arena, the world number two had to fight past a first set nail-biter to finally shake off Riske, 7-6 6-3. Both players had plenty of break point opportunities, with Pliskova breaking five times from 12 opportunities, while Riske took three of 10. Unfortunately for the American, her serve let her down massively, serving a whopping 11 double faults for just one ace and getting her first serve in 59 per cent of the time. It was still better than Pliskova (58 per cent), but the Czech had eight aces and only two double faults and managed to survive some tennis that was not at her best, but good enough to win.