The Brazilian won against Swiss qualifier Viktorija Golubic (6-3, 7-5), Spaniard Cristina Bucsa (6-2, 6-1) and Frenchwoman Clara Burel (6-2, 6-2) earlier in the week.
In the previous rounds of the tournament, Siniakova, ranked No 36, won against Japanese qualifier Sayaka Ishii (6-7 (5), 6-3, 7-6 (5)), Spanish qualifier Jessica Bouzas Maneiro (2-6, 6-4, 7-6 (2)) and American Peyton Stearns, the No 6 seed (1-6, 6-3, 6-4).
Cleveland WTA 250, other semi-final result (Jacobs Pavilion, hard, USD 267,082):
