Juan Monaco has been forced to retire from his round one Monte Carlo Masters match against Robin Hasse with an ankle injury.
The Argentine sustained the problem as he stretched to play a shot during the third set in France.
He received medical treatment for 10 minutes on the court, where his ankle was heavily strapped.
However, the 28-year-old, who was leading the match 5-7 6-0 3-2 at the time, was unable to continue against the Dutchman.
Hasse will now face either Michael Llodra or Fabio Fognini in round two.
