Feliciano Lopez has revealed that it was "impossible" for him to continue playing through injury at the French Open.

The Spaniard was forced to retire in the first round of the contest against Florent Serra in Paris this morning due to a muscle injury.

"In the beginning, I felt it was nothing really serious, but [the] day after, I couldn't play almost," said Lopez. "I tried to rest during the weekend just to try to play today, but it was impossible."

Serra, who was leading five to love in the first set, will go up against Karol Beck or Lukasz Kubot in the next round.