Marseille began life after Roberto De Zerbi with a 2-2 draw at home against Strasbourg in Ligue 1 on Saturday despite leading by two goals late into the second period.
The Italian coach left the south coast club earlier in the week following last Sunday's 5-0 thrashing to fierce rivals Paris Saint-Germain.
Goals from Mason Greenwood and Amine Gouiri seemed to be enough to give interim boss Jacques Abardonado a vital three points, but Sebastian Nanasi's second-half strike set up a nervy finale at the Stade Velodrome before Joaquin Panichelli converted a penalty deep into injury time.
The late collapse condemned Marseille to remaining in fourth place, 11 points off the pace.
The draw kept Gary O'Neil's Strasbourg seventh in the table on 31 points.
With large swathes of the stands empty as protesting Marseille fans waited until the 15th minute to come in, the visitors nearly grabbed the lead in the opening five minutes when Martial Godo headed onto the woodwork.
That warning woke up Marseille and former Manchester United forward Greenwood outpaced Andrew Omobamidele and dinked home on 14 minutes – one minute before Marseille's fans behind the goals came in.
Strasbourg dominated the remainder of the half but failed to break down Marseille.
Abardonado's charges punished the visitors two minutes after halftime as Gouiri fired his fifth goal of the league campaign.
The away side continued to see the most of the ball, but as they failed to make a breakthrough, O'Neil made changes.
Nanasi came on just after the hour and netted in the 73rd minute after good wide play by Godo.
Marseille looked set to see out the win until Emerson Palmieri caught Gessime Yassine while trying to clear the ball and the referee pointed to the spot deep into stoppage time.
Panichelli stepped up and dispatched the resulting spot-kick in the 97th minute to ensure the spoils were shared at the Velodrome.
Later, Lens can go back top of the table when they visit Paris FC after Lille host Brest.