Novak Djokovic, Roger Federer, Andy Murray, Serena Williams, and Agnieszka Radwanska have all reached the Australian Open semifinal stage as expected, but they are joined in the last four by three surprising names:  Angelique Kerber, Milos Raonic, and Johanna Konta.

Kerber is the least surprising of the three. Before this fortnight, she had already reached two Grand Slam semifinals and two quarterfinals, and she has often faced the best players in the world in big matches. However, her last-eight triumph was her first-ever win over Victoria Azarenka, which makes it a very significant moment in her career.

The German had a highly impressive 2015 season, winning four WTA titles, all at the Premier level, and a world-leading total of 53 matches – equal with Serena. She also won 44% of her return games last year, which was the sixth-highest percentage on tour. Given these factors, her impressive win over Azarenka, and the knowledge that she is currently playing the best tennis of her career, could Kerber be on the verge of truly breaking into the WTA elite?

In previous years, she almost certainly would have lost a quarterfinal against a two-time Grand Slam champion. But perhaps her consistent results in 2015 have given Kerber the confidence she needs to push on to the next level. According to her, practicing with the legendary Steffi Graf before Indian Wells last March has been instrumental in her improved performances. Kerber said that “(Graf) taught me actually that I'm on a good way and to try to believe in myself. I was trying to do it in the last few months. I was going out there today with a lot of confidence and trying to believe really in myself and just going for my shots, trying to play good tennis.”

Her belief and aggressive intent really shone through in her 6-3 7-5 victory over Azarenka. Kerber seized the moment and took her chance to make the last four with aplomb. Admittedly, she punished an opponent who, in her own words, was flat and 10% below her best in every area. As Azarenka said, “That's not going to win matches in quarterfinals. You have to bring it, and I didn't.” Kerber definitely brought it, producing arguably the best tennis of her career, and she will now be the strong favorite to come through her semifinal against Konta.

Most observers would call Konta’s run to the last four in Melbourne unexpected, and they are right – up to a point. When you examine what has happened in the Brit’s half of the draw, and take into account her significant improvement last year, it is not as surprising as it first seems. According to the seedings, Konta was due to play an opponent in round three – Sabine Lisicki – who is potentially very dangerous to her due to her massive serve and powerful groundstrokes, followed by another player with enough weapons to trouble her in round four – Karolina Pliskova. She was then due to play No. 2 seed Simona Halep in a quarterfinal, which would have been a very tough match. Despite all her lucky breaks in avoiding those players, arguably the biggest slice of fortune to come Konta’s way was the unfortunate injury to Madison Keys in her match against Shuai Zhang. If Keys had not been injured, had won that match, and then had played close to her best against Konta, the British woman would surely have stood little chance of winning.

All of that leaves Konta’s first-round win, over eighth seed and legend of the women’s game Venus Williams, as arguably her most surprising. Take nothing away from her. She was impressive in that match, and she has been impressive since, particularly in the way she has responded to pressure situations in her matches, so she fully deserves her place in the last four. However, it is impossible not to wonder whether she would have gotten there if someone like Halep or Keys had faced her at some point. Will her fairytale run continue against Kerber? British pundits Virginia Wade and Greg Rusedski believe it will, but if the No. 7 seed plays at close to her best level, she will surely be too strong for Konta. Whichever woman wins, it will be her first-ever Grand Slam final appearance.

In a largely predictable men’s competition at the Australian Open, Milos Raonic has emerged as the one surprise name in the semifinal line-up. And it’s certainly refreshing to see him there challenging the established “Big Five” (if you include Rafael Nadal and Stan Wawrinka). He had to beat Wawrinka on his way to the last four, and, although the Swiss was not at his best in the first two sets of the match, Raonic played some of the best tennis of his career.

So what’s changed in the Canadian’s game? He has improved his volleying, looking to come into the net and finish points whenever he can, and this makes him even more dominant on serve than he was previously. This puts inherent pressure on any opponent, since going down a break against Raonic in a set can be a really difficult situation to retrieve. Wawrinka found this out in the three sets he lost 6-4, 6-3, and 6-3. The No. 13 seed is also more aggressive when returning, sometimes chipping and charging to take up positions at the net, and at other times relying on his powerful forehand.

Despite his impressive victory over Wawrinka, and a solid follow-up win over Monfils in the quarterfinal, Murray is likely to prove too difficult a challenge for Raonic in the last four. The Scot is a master at taking down the big servers of the game, and those strengths will serve him well against the Canadian. However, Raonic looks to be in the best form of his career, and if Murray falters, as Wawrinka did, he could capitalize and seal an improbable place in his first-ever Grand Slam final.