Toulouse fly-half Lionel Beauxis missed a 79th minute conversion to allow Montpellier to escape with a 10-8 victory in Saturday's Top 14 clash at Stade Yves Du Manoir.
The result could prove crucial for both team's ambitions for a home play-off. A losing bonus point for Toulouse moves the defending champions six points clear of fourth-placed Castres with two rounds remaining while Montpellier are now just one point further back (provisionally) in fifth.
Montpellier led 3-0 at the end of the hard-fought first half that saw the hosts dominate possession but unable to break through the Toulouse defence.
Beauxis drew the visitors level early in the second period but Montpellier's Fijian wing Timoci Nagusa was first to cross the whitewash shortly afterwards with a brilliant solo effort from the halfway line.
Toulouse replacement centre Gael Fickou scored in the 78th minute at the end of a classic flowing Toulouse attack but Beauxis, who endured a miserable day with the boot, failed with the conversion, his fourth miss in five attempts, leaving Montpol with the spoils.
Montpellier:15 Benoit Sicart, 14 Timoci Nagusa, 13 Thomas Combezou, 12 Hamish Gard, 11 Taleta Tupuola, 10 Santiago Fernandez, 9 Benoit Paillaugue, 8 John Beattie, 7 Alexandre Bias, 6 Fulgence Ouedraogo, 5 Thibaut Privat, 4 Mamuka Gorgodze, 3 Maximiliano Bustos, 2 Agustin Creevy, 1 Mikheil Nariashvili.
Replacements: 16 Charles Geli, 17 Yvan Watremez, 18 Mickael De Marco, 19 Alex Tulou, 20 Julien Tomas, 21 Paul Bosch, 22 Martin Bustos Moyano, 23 Giorge Jgenti.
Toulouse: 15 Yoann Huget, 14 Vincent Clerc, 13 Florian Fritz, 12 Clement Poitrenaud, 11 Maxime Medard, 10 Lionel Beauxis, 9 Jean Marc Doussain, 8 Edwin Maka, 7 Thierry Dusautoir, 6 Jean Bouilhou, 5 Patricio Albacete, 4 Yoann Maestri, 3 Census Johnston, 2 William Servat, 1 Gurthro Steenkamp.
Replacements: 16 Jaba Bregvadze, 17 Jean Baptiste Poux, 18 Romain Millo Chlusky 19 Yannick Nyanga, 20 Luke Burgess, 21 Gael Fickou, 22 Yann David, 23 Vasil Kakovin.
Referee: Jérôme Garcès