London (AP) - Roger Federer has won for the first time in four years against Novak Djokovic and after an impressive Wimbledon revenge reached the semi-finals of the ATP World Championship.

The 38-year-old professional tennis player from Switzerland won against the six-year-younger Serb with 6: 4 on Thursday before the no less explosive preliminary round final in the other group with a semi-final chance for Alexander Zverev, Rafael Nadal and Daniil Medwedew , 6: 3 through.

Thus Federer pulled after a performance of the extra class as group second behind the Austrian Dominic Thiem in the semifinals on Saturday. In 49th place with Djokovic it was the 23rd win for Federer - and what a! For the first time since the 2015 group game at the ATP Finals Federer again beat Djokovic.

No room remained empty in the O2 arena in East London, when the two long-standing rivals entered the arena - as always staged at this event with plenty of noise and light effects. The match confirmed the assessment of observer Boris Becker, who had spoken of "one of the best ATP finals in years" and also in view of the long-running Djokovic against Federer in the interview of the broadcaster Sky said: "So much better it is not in tennis."

Much better than in the first sentence was not synonymous with Federer. He scored the break for 2: 1 and after 35 minutes he won the first round with an ace and a match to go to zero. The Swiss made only one slight mistake in the first round. He controlled and dominated a variety of rallies, banged on strong and was not disturbed by the wildest Serbian fan calls between the points.

In the first game of the second set Federer again offered two breakballs, which he forgave. "Let's go, Roger" chants alternated with "Nole" calls. At the score of 1: 2 Federer defended a break ball after a spectacular rally - and took his turn in the next game Djokovic from the service.

With the simple title "Showdown", the tournament organizers had overwritten their day program in glossy optics. And the evening duel kept the promise until the last rally.

On a similar spectacle, the audience may look forward to Friday - albeit not in the pure form of the direct duel to progress, but in a complicated threesome constellation. If Zverev wins against Nadal and defeat Stefanos Tsitsipas on Friday (21.00) and the "Mammutaufgabe" (Boris Becker) against Medvedev, he is in the semifinals - regardless of the outcome of the match between the world ranking first Nadal and the already qualified Tsitsipas (15.00 / all Sky).

"I can decide if I'm still here on Saturday or not. It's in my hands, "said defending champion Zverev. However, the fact that even Medvedev can still make progress despite his two defeats adds to pressure: with a two-set win against Zverev and a previous defeat of Nadal against Tsitsipas.

Information about the tournament

ATP profile Zverev

Schedule ATP Finals

ATP profile Nadal

ATP profile Medvedev

ATP profile Tsitsipa

ATP world ranking singles

direct comparison Zverev - Tsitsipas

Scenarios for semi-final move-in

direct comparison Zverev - Medvedev