Second-half substitute Jose Saez scored two minutes into injury-time to earn Valenciennes a 1-1 draw that keeps Marseille in the lower reaches of Ligue 1.
Last season's runners-up have yet to find any sort of rhythm so far this season and this was just their seventh point from eight games.
It had looked for so long as though they would go home with the win, though, with Souleymane Diawara giving them an early lead and then some resolute defending putting them close to the finish line, with their task made all the harder by Rod Fanni's first-half dismissal.
Fanni was shown a straight red card for a vicious-looking challenge on Foued Kadir that saw the latter leave the field unconscious, but Marseille were given a let-off when Gregory Pujol's penalty was saved.
But unheralded Belgian Saez would dash their hopes, heading in his first goal of the season at the second attempt.
Despite leaving it late, Valenciennes were a presence throughout the game and Pujol had the first chance, testing Steve Mandanda from distance.
Marseille quickly kicked into gear, though, and took the lead in the 16th minute when Diawara came in to volley home at the back after Alou Diarra had flicked a Mathieu Valbuena corner into his path.
Valenciennes responded and Pujol played in Gael Danic who wasted a good opportunity, before Mandanda could only watch as Renaud Cohade rattled his bar with a free-kick.
The game then turned sour, with Fanni dismissed after the clash with Kadir, whose condition was still the major concern as Mandanda went to his right and kept out Pujol's spot-kick in first-half injury time.
It took a while for normality to resume, and Marseille nearly took a bigger lead when it did, Loic Remy crunching a shot into the post just shy of the hour.
But Valenciennes kept going and wasted a number of promising openings, including Pujol going agonizingly wide, before Saez headed in Vincent Aboubakar's cross at the second attempt after his first header was saved by Mandanda.
