Defending champion Stan Wawrinka diced with danger but managed to avoid an ignominious first-round exit at the French Open on Monday, scrambling past Czech Lukas Rosol in five sets.
Twice the Swiss third seed trailed by a set on a cold and damp Philippe Chatrier Court but he dug himself out of trouble to win 4-6, 6-1, 3-6, 6-3, 6-4.
The last time a defending champion lost his opening match was Australian Lew Hoad in 1957.
For a while, with 59th ranked Rosol playing inspired tennis, Wawrinka looked in grave danger of becoming the first reigning men's singles champion at Roland Garros since tennis turned professional in 1968 to lose in the first round.
Wawrinka needed to save two break points early in the fourth set as Rosol eyed a shock on the similar scale to his victory over Rafael Nadal at Wimbledon in 2012.
Only last week the Swiss had bested Rosol (in the semi-finals) en route to winning the title in Geneva.
A day that began two hours late after torrential rain ended with world number two Murray hanging on against 37-year-old Czech qualifier Radek Stepanek having lost the opening two sets in the Philippe Chatrier Court gloom.
Murray, second favourite to de-throne Wawrinka after world number one Novak Djokovic, had to wait until 7pm local time to take on tricky Stepanek, the oldest man in the draw.
He might have hoped to polish off the world number 128 in time for dinner, but Stepanek had other ideas.
With Murray off-key, Stepanek used his full range of slices, pinpoint forehands and bamboozling drop shots to torment the twice grand slam champion.
A fraught Murray dropped serve with a double-fault and conceded the opening set with a misfired forehand.
The second set went the same way as Stepanek delighted a sparse crowd with his repertoire.
Murray, scolding himself into action, waltzed the third set and was a break up in the fourth. Yet Stepanek will return on Tuesday believing he can become the oldest man to win a round at Roland Garros since Jimmy Connors (aged 38) in 1991.
In the women's singles Garbine Muguruza recovered after losing the first set to advance to the second round.
The fourth-seeded Spaniard, a two-time quarter-finalist, beat Slovakia's Anna Karolina Schmiedlova 3-6, 6-3, 6-3.
However, the 22-year-old Wimbledon runner-up was far from impressive in her opening match.
After dropping the first set, Muguruza had to save nine break points just in the opening game of the second set as Karolina Schmiedlova kept up the pressure.
The 37th-ranked Slovak, who has won just one match all year, had 21 break points against the Spaniard. However, she managed to convert just four of them.
Muguruza will take on French wildcard Myrtille Georges, the world number 203, for a place in the last 32.
Simona Halep, beaten by the currently suspended Maria Sharapova in the 2014 final, made short work of her opener, dropping only two games against Japan's Nao Hibino.
Russian Svetlana Kuznetsova, champion 10 years ago, also progressed, beating Yaroslava Shvedova 4-6, 6-1, 6-4 on a day in which seeded players generally flourished.
Men's fifth seed Kei Nishikori, a semi-finalist in Madrid and Rome, followed Wawrinka on to Chatrier with his job already half done against Simone Bolelli.
The Japanese carried on where he left off before rain halted play on Sunday, easing to a 6-1, 7-5, 6-3 victory.
He was joined in the second round by eighth seed Milos Raonic, who had a straight-sets win over Serbia's Janko Tipsarevic but former top-tenner Grigor Dimitrov bowed out to 22nd seed Viktor Troicki.