Haas needed a strong third set to get past Argentina's Horacio Zeballos 6-3, 5-7, 6-2 in one of the day's quarterfinal matchups.
His next opponent will be Italian Paolo Lorenzi, who logged a 7-6 (8-6), 6-7 (4-7), 6-4 upset of fourth-seeded Juan Monaco.
Also advancing was crowd favorite Bellucci, who breezed past Slovakia's Martin Klizan 6-3, 6-3.
Joining him in Saturday's other semifinal will be Federico Delbonis. The Argentine dismissed Spain's Albert Montanes 6-4, 6-3.