Updated

Top seed Philipp Kohlschreiber suffered a second-round upset, while two-time defending champion Robin Haase resumed his winning ways at the Kitzbuhel Cup tennis event on Tuesday.

Argentine Leonardo Mayer tackled the German Kohlschreiber 6-4, 7-6 (7-4) on the red clay at Kitzbuhel Tennis Stadium. Kohlschreiber was last year's runner-up here to Haase, who fired 10 aces in getting past Frenchman Guillaume Rufin 6-4, 7-6 (7-4) in some opening-round action.

Haase, who was last week's runner-up in Gstaad, will meet German Daniel Brands on Wednesday.

Another second-round result saw eighth-seeded Spaniard Marcel Granollers drill Horacio Zeballos 6-0, 2-0, as the Argentine retired with a rib injury after losing eight straight games on Day 2, while another upset came when Brands doused fifth-seeded Argentine Carlos Berlocq 7-6 (7-4), 2-6, 6-2 in round one.

Additional first-round wins came for Romanian Victor Hanescu, Czech qualifier Jan Hajek, wild card and Austria's own Andreas Haider-Maurer, and Spaniard Guillermo Garcia-Lopez, who titled here back in 2009.

Second-round matches will come Wednesday for seeded players Juan Monaco of Argentina, Spaniard Fernando Verdasco, long-time Austrian favorite Jurgen Melzer, and Spain's Albert Montanes. Monaco was the Kitzbuhel titlist in 2007; Montanes was the 2011 runner-up to Haase; Melzer was a runner- up here in 2008; and Verdasco was a runner-up back in 2005.

The winner of this $540,000 tournament will earn $98,000.