Paris: Rafael Nadal's bid for an historic eighth French Open title was almost spectacularly derailed by big-hitting German Daniel Brands. (Agencies)
But there were no such problems for defending women's champion Maria Sharapova who eased past Taiwan's Hsieh Su-Wei in just 54 minutes, surrendering only eight points on serve.
Seven-time champion Nadal dropped the opening set of a Grand Slam for the first time in his career before he prevailed 4-6 7-6 (7/4) 6-4 6-3 against a player who had lost all four of his previous matches in Paris.
The Spaniard, who before this year had only lost once in 53 outings at Roland Garros, came into the tournament having won six titles in eight finals since he returned from a seventh-month injury lay-off.
But the 26-year-old was caught cold by world number 59 Brands who unleashed a fearless barrage of attacks off both sides to leave the third seed reeling.
It was almost a carbon copy of the tactics employed by Robin Soderling, the only man to beat Nadal in Paris four years ago, and Lukas Rosol, who dumped the Spaniard out of Wimbledon last year.
Brands even led 3/0 in the second set tie-breaker as he appeared poised to deliver the first defeat of a men's champion in the opening round in tournament history.
But Nadal eventually found his rhythm to steady the ship as the 25-year-old German eventually ran out of firepower.
Paris: Rafael Nadal's bid for an historic eighth French Open title was almost spectacularly derailed by big-hitting German Daniel Brands.