Taylor Fritz beat the great Rafael Nadal in his first ATP Finals match ©Getty Images

Rafael Nadal's quest for a first Association of Tennis Professionals (ATP) Finals title is off to an inauspicious start after he was beaten by Taylor Fritz.

American Fritz - making his ATP Finals debut - won 7-6, 6-1 at Turin's Pala Alpitour.

Spaniard Nadal has won a record 22 men's Grand Slam singles titles, an Olympic gold medal and 92 ATP Tour tournaments - but never this one.

Nadal is a two-time runner-up but now faces an uphill battle just to make it out of the Green Group.

Norway's Casper Ruud won the pool's other match today.

Ruud, seeded third and coming off a breakout year which featured two Grand Slam final appearances, beat Canada's Felix Auger-Aliassime 7-6, 6-4.

Nadal is the top seed.

The Red Group is set to grace the hard courts tomorrow.

Serbia's 21-time Grand Slam champion Novak Djokovic, Greek second seed Stefanos Tsitsipas and "neutral" Russians Daniil Medvedev and Andrey Rublev make up the Red Group.

Both world number one Carlos Alcaraz, from Spain, and Germany's Alexander Zverev - the reigning Olympic and ATP Finals champion - are absent.