Stefanos Tsitsipas and Alex de Minaur moved into the semi-finals at the Next Gen Finals in Milan after victories on Wednesday.
The pair won their opening matches – against Jaume Munar and Liam Caruana, respectively – and further triumphs made the duo the first two through to the last four.
Top seed Tsitsipas was in dominant form against Frances Tiafoe, beating the American, who had also prevailed in his opening contest, 4-3 (7-3) 4-3 (7-5) 4-2.
"I never dropped my performance, I always stayed at 100 per cent almost, so I am very satisfied that I managed to stay calm and play every point like a match point," said the Greek.
De Minaur was up against 2017 finalist Andrey Rublev and was taken to four sets but still came through.
Rublev took the second to threaten a fightback, but he was outclassed in the end 4-1 3-4 (5-7) 4-1 4-2.
The Russian is still in with a chance of reaching the next stage, however, with wildcard Caruana up next, the Italian having lost again to Taylor Fritz.
Caruana won the opener and then took the third deep into a tiebreak before coming up short, 1-4 4-1 4-3 (11-9) 4-2.
In Group A with Tsitsipas, Hubert Hurkacz required all five sets to defeat Munar 4-2 4-2 2-4 3-5 (5-7) 4-1.