Gasquet, fresh from his ATP Tour victory in Nice at the weekend, produced a blistering start, taking Murray to the brink of defeat by claiming the first two sets.
But in a repeat of their 2008 Wimbledon encounter, brave Murray hit back in tremendous style, coming back from a break down to take a tense third set before eventually sealing a thrilling 4-6, 6-7 (5-7), 6-4, 6-2, 6-1 victory in four hours and four minutes.
Crowd favourite Gasquet arrived in Paris on the back of a 10-match unbeaten run on clay, and he picked up where he left off from Nice, taking the game to Murray with a flurry of top-class winners, in particular with his brilliant backhand.
Indeed, Murray just couldn’t make any inroads on the Gasquet serve and the Frenchman took full advantage, adding a marathon second set on a tie-break.
A break in the five game of the third set left the fourth seed floundering, but in true Murray spirit, back he came, breaking his opponent twice in the next two games before holding out to halve the deficit.
From then in was game over. Gasquet began to tire and was also treated for the thigh injury for which he complained about at the weekend, while Murray grew in confidence, rattling through the fourth set in just over half an hour with two breaks of serve before inevitably wrapping things up in a rather one-sided decider.
Murray now faces Argentine Juan Ignacio Chela in round two, and will be joined there by world No1 Roger Federer, who began the defence of his title with a 6-4, 6-1, 6-2 victory over Australia’s Peter Luczak.
Third seed Novak Djokovic dropped a set against Kazakhstan’s Evgeny Korolev but came through strongly to win 6-1, 3-6, 6-1, 6-3.