ATP Finals: Stefanos Tsitsipas earns first-ever win over Daniil Medvedev

Stefanos Tsitsipas finally found a way to win against Daniil Medvedev, beating the Russian 7-6 (5), 6-4 Monday in their opening match at the ATP Finals.

The fourth-seeded Medvedev entered the match with a 5-0 record against Tsitsipas but couldn't earn a single break point on the indoor hard court at the O2 Arena.

Instead, the sixth-ranked Tsitsipas converted the only break of the match to take a 5-4 lead in the second set and then clinched the victory with an overhead forehand at the net.

Both players are making their debut at the year-end tournament for the world's top eight players, which features a round-robin stage before the semifinals. Medvedev established himself as one of the best hard-court players on tour this season, reaching the U.S. Open final and winning four titles on the surface.

But Tsitispas — the first Greek player to qualify for the ATP Finals — used an aggressive forehand to keep the Russian from dictating the match, coming to the net 26 times and winning 22 of those points.

In the first-set tiebreaker, Tsitsipas hit a forehand volley winner to go ahead 6-5 and then clinched the set when Medvedev netted a forehand.

In the late match, top-ranked Rafael Nadal was to play defending champion Alexander Zverev. Nadal, who has a 5-0 record against Zverev, is looking for his first title at the event.

In the other group, Novak Djokovic beat Matteo Berrettini on Sunday while Roger Federer lost to Dominic Thiem.