Top-seed Marat Safin crashed out of the Masters Series in Monte Carlo after losing in the first round to Frenchman Arnaud Di Pasquale.
Safin conceded five service games on his way to a straight sets defeat in a 52-minute match that revived fears over the Russian's loss of form since injuring his back in March.
The US Open champion grimaced with frustration and tossed his racket several times in trademark displays of anger as he made a string of unforced errors.
The 21-year-old struggled to adapt his shot-distance, placing balls wide and long - at one point sending an easy smash several metres beyond the baseline.
Unseeded Di Pasquale was similarly error-prone in the first set, but remained in control for the crucial points.
The victory was a major boost for Di Pasquale, who is ranked 75th in the 2001 Champions Race and has only one career title under his belt.
Safin is ranked number one in the ATP's rolling 52-week ranking system thanks to his strong performance last year, in which he won seven ATP titles.
But he is 20th in the 2001 Champions Race, with no titles so far this season.