Stefanos Tsitsipas defeated Alexander Zverev 6-1, 6-4 to extend his winning record against the German in five straight wins. The singles match was the second match between the two nations on day three of the inaugural ATP Cup.
The win also helped a securing a draw between Greece and Germany to 1-1 and thus take the match-up to the deciding set to the doubles match.
Tsitsipas will pair with Michail Pervolarakis for the decider against Kevin Krawietz and Andreas Mies of Germany.
It was another frustrating day for Zverev on the court and he was reportedly arguing with his teammates, Boris Becker, and his father and was also heard mouthing expletives in frustration.
Earlier in the day, Australia defeated Canada 3-0, but it was not all pleasant for the hosts since Nick Kyrigos had to pull out of the tournament because of a back injury. He was replaced by John Millman.
Team captain Lleyton Hewitt was asked about the Krygios' withdrawal, and he said, "He was a bit stiff yesterday afternoon, but also this morning. Johnny was obviously raring to go as well." Krygios was later seen courtside cheering his teammates.
Australia are undefeated in the ATP Cup after two rounds after defeating Canada 3-0. Earlier, Alex de Minaur came back from a set and a break down on Sunday to defeat world No.15 Denis Shapovalov 6-7(6) 6-4 6-2.
If Germany defeats Greece, then Australia will automatically qualify for the finals.