Taylor Fritz reached the ATP Finals title decider on Saturday by defeating Alexander Zverev in three sets, moving one win away from becoming the first American champion at the showpiece event since Pete Sampras 25 years ago.

Fifth-ranked Fritz triumphed 6-3, 3-6, 7-6 (7/3) over world number two Zverev in a thrilling match at the season-ending event in Turin.

Fritz will face either world number one Jannik Sinner or Casper Ruud in Sunday's showdown where he will bid to become the first American since 14-time Grand Slam champion Sampras in 1999 to claim the title.

James Blake, in 2006, was the last US man to make the final.

Fritz could yet have the chance to gain revenge on Sinner for being beaten in the US Open final following a gruelling match in northern Italy.

Both players had chances to take control in a topsy-turvy third set, but failed to capitalise on a host of break points before Fritz held his nerve better in the tie-break to claim a spot in the final.

Fritz managed to save three break points in game five of the third set, just when it looked like Zverev was set to take control of the match.

"That was probably the biggest turning point, I lose one of those points and that's probably it. That's kind of how it goes with playing Sascha," said Fritz, who got to the semis two years ago.

"It's awesome to come back and go a step further. It's an honour to be here so to be in the final is amazing."

Home hope Sinner will be backed by a passionate crowd in the day's main event, the Italian aiming for his first Finals title after an exceptional year in which he won seven tournaments, including his first Grand Slam victories at the Australian and US Opens.

He lost last year's final to Novak Djokovic, who pulled out of the tournament injured this time around and he entered the 2024 event already assured of becoming the first Italian to top the ATP end-of-year rankings.

However, he has been dogged by controversy after twice testing positive for traces of the steroid clostebol in March.

He was initially cleared by the International Tennis Integrity Agency but at the end of September the World Anti-Doping Agency appealed, seeking a ban of up to two years.