American player Learner Tien came back to defeat compatriot Alex Michelsen, while Brazil's Joao Fonseca cruised past Luca Van Assche of France in the semifinals of the Next Gen ATP Finals on Saturday.

Tien, ranked world No. 122, overcame 41st-ranked Michelsen 2-4, 4-2, 1-4, 4-0, 4-1. After falling 2-1 behind in sets, Tien displayed exceptional baseline play, winning seven consecutive games in the final two sets to secure the victory.

After defeating his long-time friend, Tien said, "I am really happy with the win but I hate it was against him, but that is just how it goes."

In the other semifinal, world No. 145 Fonseca cruised past Van Assche 4-2, 4-2, 4-1, marking his fourth consecutive win in the tournament. Fonseca now holds the distinction of being the lowest-ranked finalist in the tournament's history.

"I did what I talked about with my coach. He didn't have too many chances because I was playing so aggressively and making all the shots. There is one more match to go, and I hope I can [go] for it," Fonseca said after the match.

The final between Tien and Fonseca will take place on Sunday night. The two players met during the group stage, with Fonseca securing a four-set victory.