Women’s tennis has a new number one for the first time in 186 weeks. And it’s not Garbine Muguruza. Instead, it’s the other player who defeated Serena Williams in a Grand Slam final in 2016 who has slipped, somewhat under the radar, all the way to the top.

On Thursday night, 28-year-old Angelique Kerber of Germany became the oldest woman to take over the world number one ranking. This is not as huge a shock as it might appear to be to casual tennis fans, because all summer Kerber had been in hot pursuit of the American.

This has been a phenomenal year for Kerber. She began by winning the Australian Open. She lost to Williams in the Wimbledon final, and followed it up with a strong summer on the hard courts that included an Olympic silver medal in Rio. In the final of Cincinnati, she faced Karolina Pliskova, where she was poised to take over the number one ranking if she were to win. That time, Pliskova denied her the opportunity. But, ironically, on Thursday, it was Pliskova who handed her the number one ranking by beating Williams in straight sets in the US Open semi-final. Now the two will meet once more in the women’s final, the first major final of the year without Serena.

Born in Bremen to a Polish father and a German mother, Kerber, who began playing tennis at age three, lives in Puszczykowo, Poland, where her grandparents run the Centrum Tenisowe Angie tennis academy. But her heart, she said in an interview, “beats for Germany.” Her career breakthrough came at the US Open in 2011, when Kerber entered the tournament ranked number 92, and reached her first Grand Slam semi-final where she lost to eventual champion Samantha Stosur. Despite her reputation for consistency, Kerber underachieved for the next few years, however, and reached a new low in 2014, when she suffered early losses at the Australian Open, Antwerp, and Doha, a spiral that led her to seriously re-evaluate her life and career. She said in an interview, “I couldn’t find a way out and started asking myself: Why am I even doing this? I didn’t feel any joy or motivation. I had to change something.”

Turning to her idol

One of the people she turned to then was her idol and the last German woman to be world number one: Steffi Graf. She accepted Graf’s longtime invitation to visit Las Vegas where the two practiced and talked. “She got rid of my doubts,” Kerber said, attributing much of her subsequent success to that time spent with her mentor. Perhaps that gave her some extra motivation in the Australian Open final this year to prevent Serena Williams from equaling Graf’s Open Era record of 22 majors.

A natural righty, like Rafa Nadal, Kerber plays tennis with her left hand. In 2015, she won four WTA tour titles. But this has been, by far, her best season.

When she’s not playing tennis, Kerber enjoys playing cards with her coach Torben Beltz. Until a couple of years ago, Angie, as she is known, focused almost solely on tennis. But now, she tries to take time off for some relaxation. In an interview with Telegraph Sport, she recently said, “Now I try to relax a little bit more and enjoy every moment of every day. If it’s somewhere close to the sea, I try to go there, or go shopping, go to the cinema, go to some musicals or visit something special - like when you are in Paris you go to the Eiffel Tower.”

Looking for revenge

On Saturday, in the US Open women’s final, the new number one will take on Pliskova in a rematch of the Cincinnati final. But despite her ranking and Grand Slam record this year, she is not a heavy favourite to win. In fact, some are picking Pliskova, the first Czech woman to reach the US Open final since Helena Sukova in 1993. Pliskova beat both Williams sisters in this event and is currently on an 11-match winning streak. Karolina, whose identical twin sister Krystina is also a professional tennis player, is one of the biggest servers in the women’s game. The six-feet one-inch tall Czech has served 439 aces this year. On the other hand, Kerber is one of the best returners on the tour. In 51 matches this year, Kerber has won 46.9% of return points and 43.1% of return games. So the women’s final is almost certain to be a fascinating contrast in styles. Pliskova, 24, will be looking for her first Grand Slam title, while Kerber will be looking simply for revenge.

For the second successive year, Serena Williams failed to make it to the US Open final, losing to lower-ranked players in front of a home crowd. For the second successive year, we will have new champion in New York. Whether it’s Kerber or Pliskova, this year, women’s tennis has proved the winner with its unexpected storylines, rising stars, and breakthrough moments. No matter what happens in the final, a former German champion will no doubt be happy to see her protégé play the final, safe in the knowledge that no one is going to overtake her Grand Slam record just yet.

Oindrila Mukherjee tweets here.