Argentine qualifier Federico Delbonis reached his second career ATP quarter-final on Thursday when he upset third-seeded Thomaz Bellucci of Brazil 6-2 7-5 in the Vina Del Mar VTR Open.

Bellucci, the champion two years ago, dropped his serve four times to Delbonis.

The qualifier’s opponent in the quarters will be seventh-seeded Carlos Berlocq, who overwhelmed fellow Argentine Diego Junqueira 6-1 6-0.

Second-seeded Juan Ignacio Chela of Argentina defeated countryman Horacio Zeballos 6-4 7-6 (7-2), setting up a quarter-final against Brazilian Joao Souza, who upset Chile’s Fernando Gonzalez 6-3 7-6 (8-6).

In the other quarter-finals of the claycourt event, Juan Monaco will play Albert Montanes and Federico Gil goes against Jeremy Chardy.