Top seed Stanislas Wawrinka of Switzerland was bundled out of the Swiss Open on Thursday when he lost 6-4, 6-4 to unseeded Thomaz Bellucci in the second round.
The 21-year-old Brazilian left-hander, ranked 119th in the world, controlled the game from early on and service breaks in the final game of the first set and the sixth of the second were enough to give him the victory.
Wawrinka, who has dropped to 24th in the rankings after breaking into the top 10 last year, won only 12 of 53 points on return of serve and did not manage a break point as he disappointed the home crowd.
Wawrinka followed German second seed Philipp Kohlschreiber, beaten in the first round by Romania's Victor Crivoi, in making an early exit.
Bellucci will meet German sixth seed Nicolas Kiefer, who beat Ivan Navarro of Spain 6-3, 6-7, 6-2, in the quarter-finals.
