Jean-Marc Doussain's missed conversion denied Toulouse the chance to snatch a late draw, as they lost 31-29 to Montpellier on Sunday.
Timoci Matanavou's remarkably late try in the 88th minute looked to have taken the win away from Jake White's Montpellier at the death in a high-scoring contest.
Demetri Catrakilis scored 16 points for the visitors including a drop goal to go with two tries from Timoci Nagusa.
Doussain's penalty opened the points after three minutes, equalised by Catrakilis, before Montpellier scored the opening try.
Benoit Paillaugue's kick behind the Toulouse defence following a turnover gave Nagusa enough space to chase and finish, converted by Catrakilis.
Four minutes later the wing was in for his second try, with Paillaugue and Francois Steyn heavily involved as the winger did well out near the right touchline to score. This time Catrakilis couldn't convert, but Montpellier were out to a healthy lead at 15-3.
A Doussain three-pointer was cancelled out by a drop goal from Catrakilis and the two kickers traded further points to round out the half, with two penalties by Doussain to one from Catrakilis making it 21-12 at the break after Toulouse had lost Florian Fritz to the sin-bin.
Building off their bright start Montpellier's third try followed, Paul Willemse this time pouncing on a loose pass from Luke McAlister to finish.
Catrakilis converted to open up a huge 16-point advantage for the visitors, although with plenty of time remaining.
David Mélé set up a try for Paul Perez to help Toulouse fight back and narrow the gap to 28-19 after Doussain's conversion, and with a second try five minutes later by Luke McAlister suddenly Toulouse had a chance.
Doussain however failed to convert and another penalty by Catrakilis opened up a crucial seven-point gap as Toulouse threw everything they had at Montpellier, who went down to 14 men after a yellow card for Robins Tchale-Watchou.
But despite Matanavou's score, an absurd eight minutes of time after the hooter sounded, Montpellier escaped with the win after Doussain's costly miss.
Tries: Perez, McAlister, Matanavou
Pens: Doussain 4
Yellow Card: Fritz
Tries: Nagusa 2, Willemse
Cons: Catrakilis 2
Pens: Catrakilis 3
Drop Goal: Catrakilis
Yellow Card: Tchale-Watchou
Toulouse: 15 Luke McAlister, 14 Vincent Clerc, 13 Toby Flood, 12 Florian Fritz, 11 Paul Perez, 10 Jean-Marc Doussain, 9 David Mélé, 8 Gillian Galan, 7 Imanol Harinordoquy, 6 Talalelei Gray, 5 Patricio Albacete, 4 Gregory Lamboley, 3 Census Johnston, 2 Christopher Tolofua, 1 Vasil Kakovin
Replacements: 16 Julien Marchand, 17 Cyril Baille, 18 Edwin Maka, 19 François Cros, 20 Yacouba Camara, 21 Alexis Palisson, 22 Timoci Matanavou, 23 Dorian Aldegheri
Montpellier: 15 Ben Lucas, 14 Timoci Nagusa, 13 Robert Ebersohn, 12 Frans Steyn, 11 Jesse Mogg, 10 Demetri Catrakilis, 9 Benoit Paillaugue, 8 Akapusi Qera, 7 Wiaan Liebenberg, 6 Fulgence Ouedraogo, 5 Thibault Privat, 4 Paul Willemse, 3 Jannie du Plessis, 2 Mickael Ivaldi, 1 Yvan Watremez
Replacements: 16 Bismarck du Plessis, 17 Oleg Ishchenko, 18 Robins Tchale-Watchou, 19 Jacques Du Plessis, 20 Cameron Wright, 21 Yvan Reilhac, 22 Anthony Floch, 23 Nicolas Mas
Referee: Jérôme Garcès