Coach Gunter Bresnik was surprised by how bad his pupil Dominic Thiem played against Serbia's Laslo Djere on Tuesday. World No. 90 Djere claimed a shock first round win at the Rio Open as he lost just six games against top-seed Thiem 6-3 6-3.
Djere got broken back in the opening game of the match but broke Thiem immediately in the following game. The Austrian saved a break point in the fourth game before the Serb claimed the crucial break of the first set in the eighth game.
Both players were tied at 3-3 in the first set when Djere won five games in a row to take a 6-3 2-0 lead. Djere earned the second break of the second set in the seventh game to take a 5-2 but failed to serve out for the match in the following game as Thiem reduced the deficit to 5-3.
Despite failing to serve out for the match against the top-seed, the world No. 90 kept his focus as he broke the Austrian in the ninth game to seal the win.
Thiem, who retired his Australian Open second round clash due to fatigue, returned to action at last week's Argentina Open after skipping the Davis Cup and Cordoba Open for resting purposes.
Bresnik: "Dominic looked tired - tired and slow. You did not feel that he was in control of the game.
The Austrian made the semi-final in Buenos Aires before he was edged out by Diego Schwartzman in a tight three-setter.