Last year's semi-finalist Gilles Simon bowed out of the Monte Carlo Masters at the first round stage after a shock loss to Roberto Bautista Agut.
Frenchman Simon was seeded 11th for the prestigious clay court event but Spaniard Bautista Agut prevailed 6-3 7-6 to claim his first win at a Masters series event.
Simon claimed the first break to lead 2-1 in set one but it was a match in which breaks of serve proliferated and Bautista Agut hit back straight away.
The duo then exchanged breaks once more but Bautista Agut held for 4-3 before breaking Simon for the third time in a row.
Serving for the set, the World No. 59 fell 15-40 behind, but he fought back and saved three break points in the game before finally securing the set.
The duo proved virtually incapable of holding serve in set two and were broken four times each in the first 10 games before suddenly holding to set up a tie-break.
Spaniard Bautista Agut raced into a 6-2 lead and looked set to cruise to victory but, roared on by the crowd, Simon saved four match points to make it 6-6.
But he couldn't repeat the feat at 6-7, finding the net to send Bautista Agut through to the second round.
Simon has struggled somewhat on clay this year, losing the decisive match when France were beaten by Argentina in the Davis Cup quarter-finals recently.
The 15th seed Andreas Seppi also made an early exit, beaten 3-6 6-4 6-4 by his fellow Italian Fabio Fognini but the 12th seed Milos Raonic defeated Julien Benneteau 6-1 6-4.