Toulon clinched a last-gasp 21-20 victory over Racing 92, while there were also Top 14 wins for Brive, Grenoble, Montpellier, Pau and Clermont.
Former France international Frédéric Michalak wound back the clock as he held his nerve to convert an 80th-minute penalty to guide Toulon to a stunning victory.
Michalak’s strike came after Racing fought back from 18-3 down to lead 20-18 with three minutes remaining.
Racing hit the front for the first time when flank Wenceslas Lauret and Dan Carter crossed for late tries, which Carter also converted to turn the match on its head.
But with time up on the clock, Michalak stepped up to take the 35m pressure kick to win it for the visitors.
Further afield, Brive recorded an exciting 23-22 win against Castres, who thought they had the game won after scoring a converted try in the 77th minute. Brive, however, crossed for a five-pointer well into stoppage time to trail by a point with the kick to come. Fullback Gaetan Germain then coolly added the extras to secure a dramatic win.
Elsewhere, flyhalf Jonathan Wisniewski contributed 24 points – two tries, four conversions and two penalties – to guide Grenoble to a much needed 39-23 bonus-point win over La Rochelle.
Montpellier inflicted a 45-21 defeat on hosts Agen, with Bismarck du Plessis grabbing a brace, while Pierre Spies and Wiaan Liebenberg also crossed for one try each in the six-try romp which moved them to within two points of the log leaders.
In other results, Pau scored three unanswered tries to cruise past Oyonnax 25-3, while table-toppers Clermont edged Bordeaux 24-19.
In the only match on Sunday, Toulouse thrashed champions Stade Français 36-3.
Round 19 results:
Racing 20 Toulon 21
Brive 23 Castres 22
Grenoble 39 La Rochelle 23
Agen 21 Montpellier 45
Pau 25 Oyonnax 3
Bordeaux 19 Clermont 24
Toulouse 36 Stade Français 3
Photo: Dave Winter/Getty Images