France's Nicolas Mahut and Pierre-Hugues Herbert won the doubles fixture to force a third day of competition a the Davis Cup in Lille ©Getty Images

France triumphed in a must-win doubles fixture against Croatia in the Davis Cup final to keep their hopes of defending their title alive in Lille.

Nicolas Mahut and Pierre-Hugues Herbert claimed a crucial 6-4, 6-4, 3-6, 7-6 victory against Croatia’s Ivan Dodig and Mate Pavić at the Stade Pierre Mauroy.

The French duo, who knew defeat would spell the end of their Davis Cup defence, confidently took the first two sets but failed to convert five break-point opportunities in the third.

Dodig and Pavić made the most of a faltering Herbert serve to take the third set and force a fourth.

Momentum then swung to the Croatians as the French duo had to save three break points at the start of the fourth set.

As the French pair held their service games, an untimely double fault from Pavić with the scores at 4-5 to Herbert and Mahut put pressure on the Croatians.

Despite being 0-30 down on his serve, Pavić regained his composure to win the game and even the scores at 5-5 in the fourth set.

Mahut and Herbert took the last set 7-6 to claim France’s first victory in the tie and halve the Croatians advantage.

With the overall scores now 2-1, attention turns to the singles matches due to be played tomorrow.

First up, Jeremy Chardy must beat Marin Čilić for France to force the fifth rubber.

History is against the reigning champions, though, as no team has recovered from 2-0 down to win the trophy since Australia beat the United States in 1939.