Sao Paulo, Brazil (Sports Network) - Former top-five star David Nalbandian upset three-time champion Nicolas Almagro in Friday's quarterfinal action at the clay-court Brasil Open.

The oft-injured former Wimbledon runner-up Nalbandian upended the second- seeded reigning Sao Paulo titlist Almagro in a tough three-setter, 7-6 (7-5), 3-6, 7-6 (7-3), in 2 hours, 17 minutes. The Spanish Almagro lost despite uncorking 28 aces, as the Argentine Nalbandian prevailed with only one service break on Day 5.

Almagro beat Italian Filippo Volandri in last year's finale here and also captured this event in Costa do Sauipe in 2008 and 2011.

The 31-year-old Nalbandian's semifinal opponent will be Italian Simone Bolelli.

Also on Friday, Argentine lucky-loser Martin Alund topped the 2012 Sao Paulo runner-up Volandri 7-5, 7-6 (7-5) and Bolelli erased Spaniard Albert Montanes 6-4, 6-4.

The 2013 Brasil Open titlist will earn $82,300.

The Sports Network