Enduring a six-match winless league run, Montpellier entered the clash as an anomaly in Europe’s top five leagues, having earned 100% of their points at home.
Yet, Monaco looked determined to break that streak early on, only for Benjamin Lecomte to stand tall between the sticks, denying Eliesse Ben Seghir, Mohamed Salisu, and Takumi Minamino in quick succession.
Jean-Louis Gasset’s men soon succumbed to the pressure though, as Thilo Kehrer rose highest to meet Lamine Camara’s corner delivery into the back of the net half an hour in.
Now conceding at least one goal in each of their last 24 league outings, Montpellier’s defensive frailties left them chasing the game, with Wahbi Khazri’s tame effort from inside the box, which was easily gathered by Radosław Majecki, their only notable attempt before the break.
The hosts eventually clawed their way back 10 minutes into the second half as Al-Taamari pounced on Kassoum Ouattara's misplaced back pass, calmly rounding Majecki before slotting into an empty net to set up a thrilling final half-hour.
Having never overseen a draw in nine career meetings with Monaco, Gasset made a triple substitution past the hour mark in a bold attempt to unsettle Les Monégasques.
Lecomte then pulled off a stunning one-handed save at the other end to deny Soungoutou Magassa’s pinpoint header, perhaps sparking Montpellier’s push for a winner.
Moments later, Al-Taamari finished off a swift counterattack with a clinical low strike from a tight angle into the near post, putting Monaco on the back foot with eight minutes remaining.
Despite mounting a pushback, Adi Hütter’s Monaco struggled to get on level terms, even coming close to conceding a third when Al-Taamari sent his strike inches over the crossbar in the final minutes.
As a result, Monaco remain winless since beating Toulouse in early December, while bottom-placed Montpellier steal a first league win in over two months and just a third victory this campaign.
Flashscore Man of the Match: Mousa Al-Taamari (Montpellier Hérault SC)