LONDON — Dominic Thiem made sure this year's ATP Finals didn't begin the same way last year's ended. Thiem outlasted Stefanos Tsitsipas in a rematch of the 2019 final, beating the defending champion 7-6 (5), 4-6, 6-3 Sunday in the opening singles match of the tournament inside a largely empty O2 Arena.
In the late match, Rafael Nadal had a much easier time against newcomer Andrey Rublev, beating the Russian 6-3, 6-4 in just 1 hour, 17 minutes.
Nadal is looking to cap a season in which he earned his record-equaling 20th Grand Slam title and 1,000th match win on tour by capturing his first trophy at the ATP Finals.