Frances Tiafoe and Miomir Kecmanovic sealed their places in the last four of the Next Gen ATP Finals with straight-sets victories on Thursday.
Tiafoe joined Jannik Sinner in progressing from Group B in Milan with a 4-2, 4-2, 4-2 defeat of Mikael Ymer. Second seed Tiafoe missed out on a place in the semifinals of the season-ending event last year when he was beaten by Jaume Munar, but was not to be denied on this occasion.
The American will face top seed Alex de Minaur, who made it three wins out of three in Group A with an emphatic 4-1, 4-0, 4-2 beating of Casper Ruud.
Tiafoe went on a five-game streak from 2-1 down in the first set against the Swede at Allianz Cloud and never looked back.
The 21-year-old said: "I'm pretty stoked. I needed this. The second half of this season has been rough for me, so every match is an opportunity for me. I love this event and I want to stay. The more you win, the longer you can stay, so I'm happy to be in the semis."
Kecmanovic advanced by seeing off Alejandro Davidovich Fokina 4-1, 4-1, 4-3 (8-6) in just under an hour. The Serb will take on Sinner, who went down 4-3 (7-5), 3-4 (3-7), 4-2, 4-2 to Ugo Humbert in the final round-robin match.