Rafael Nadal started the ATP Finals on Sunday with a convincing victory over Andrey Rublev.
Defending champion Stéfanos Tsitsipás suffered a defeat against Dominic Thiem in his first group match in London.
The 34-year-old Nadal was too strong with 6-3 and 6-4 for the eleven years younger Rublev, the global number eight.
The Spaniard decided the match in the O2 Arena after one hour and nineteen minutes at his second match point.
In the first act, a break in the sixth game was enough for Nadal.
The number two in the world immediately hit a gap in the second set and did not give up that lead anymore.
Nadal has never won the ATP Finals.
He was twice in the final battle, but in both 2010 and 2013 he was defeated.
Rublev participates for the first time in the prestigious end-of-year tournament.
Stéfanos Tsitsipás started the tournament with a defeat. (Photo: ANP)
Stéfanos Tsitsipás started the tournament with a defeat.
Thiem takes revenge on Tsitsipás
In the other match in the London 2020 group, Tsitsipás lost 6-7 (5), 6-4 and 3-6 against Thiem.
The two were quite evenly matched.
Only in the third game of the second set, the Greek took care of the first break of the match.
In the deciding set, Thiem already placed a break in the second game.
The number three in the world, who won his first Grand Slam tournament in September with the US Open, no longer gave up that lead.
Tsitsipás won the unofficial World Cup tennis last year by beating Thiem in the final of all.
It is currently the only major tournament victory of the number six in the world.
On Monday, the first matches in the Tokyo 1970 group, referring to the first edition of the tournament, are scheduled.
Novak Djokovic takes on Diego Schwartzman and Alexander Zverev meets Daniil Medvedev.