Diego Schwartzman battled back from behind to defeat Stefanos Tsitsipas and secure victory for Argentina over Greece in the ATP Cup.

He won the first set, but Schwartzman, 29, rallied before sealing a fine 6-7 (5-7) 6-3 6-3 comeback win.

Earlier, Argentina's Federico Delbonis beat Greece's Michail Pervolarakis 7-6 (7-5) 6-1.

Speaking after beating Tsitsipas, world number 13 Schwartzman said: "I was just trying to think that it was his first match for two months after his elbow [injury], so I was thinking just to try and be in the match.

"I had the chance and I think I was ready. I am very happy because playing against Stefanos and being a set and a break down is not easy, but I found a way."

Argentina will face Poland on Wednesday in their final group D match with a place in the semi-finals up for grabs, after Poland beat Georgia 3-0.

World number nine Hubert Hurkacz, from Poland, recovered from a set down to beat Georgia's Aleksandre Metreveli, the world number 570, 6-7 (5-7) 6-3 6-1.

Pablo Carreno Busta and Roberto Bautista Agut won their respective singles ties in straight sets to ensure victory for Spain over Norway.

Bautista Agut upset Norwegian world number eight Casper Ruud 6-4 7-6 (7-4) after Carreno Busta had beaten Viktor Durasovic 6-3 6-3.

Chile's match with Serbia will go to the deciding doubles with the score tied at 1-1 after the singles rubbers.

After Filip Krajinovic defeated Alejandro Tabilo 6-4 3-6 7-6 (7-5) to give Serbia the early advantage, team-mate Dusan Lajovic was forced to retire injured from his match with Cristian Garin with the Chilean winning 4-6 6-4 3-0.