Zverev, who famously won the 2018 Nitto ATP Finals title, will compete at the season finale for the fifth straight year.
Daniil Medvedev, who won the US Open in 2021, is the defending ATP Finals champion having won the title in 2020.
The German has been on an impressive run of form lately, as he now holds a 25-2 record since Wimbledon.
The second seed, who earned both his 50th tour-level victory of the season and 300th tour-level career win this week, was at his impressive best on Saturday.
Andy Murray beat world No.10 Hubert Hurkacz at the Erste Bank Open in Vienna.
Alexander Zverev led 5-2 in the deciding set but failed to convert his two match points, allowing Taylor Fritz to make a comeback.
The 30th seed rattled the Greek player early on, but Tsitsipas worked his way back into the match to register a 2-6, 6-3, 6-4 victory in two hours and four minutes.
They defeated Team World’s Reilly Opelka and Denis Shapovalov 6-2, 6-7, 10-3 to give their team an incredible 14-1 victory.
The final day of the Laver Cup 2019 saw some thrilling tennis action, with Team Europe claiming the title for the third consecutive year.
Novak Djokovic is now just two wins shy of completing the calendar-year Grand Slam, a feat that hasn’t been accomplished in men’s tennis in more than half a century.