VINA DEL MAR, Chile (AP) -- Argentine qualifier Federico Delbonis reached his second career ATP quarterfinals when he upset third-seeded Thomaz Bellucci of Brazil 6-2, 7-5 in the VTR Open on Thursday.

Bellucci, the Vina del Mar champion two years ago, lost his serve four times to Delbonis.

Delbonis' opponent in the quarterfinal will be seventh-seeded Carlos Berlocq, who overwhelmed fellow Argentine Diego Junqueira 6-1, 6-0.

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

In the other quarterfinals of the clay-court event, Juan Monaco will play Albert Montanes and Federico Gil goes against Jeremy Chardy.

Read more:

SI Apps
We've Got Apps Too
Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide - from Peter King, Tom Verducci, Lee Jenkins, Seth Davis, and more - delivered straight to you, along with up-to-the-minute news and live scores.