Saracens kept their hopes of qualification Pool Three of the Amlin Challenge Cup after a Glenn Jackson-inspired 18-14 victory over Castres Olympique.
The Guinness Premiership leaders were out-scored two tries to nil by their French counterparts at Vicarage Road.
But six penalties from fly-half Jackson proved enough to take Saracens level on points with Toulon, who face Rovigo tomorrow (SUNDAY) after their game was postponed due to a frozen pitch.
Jackson broke the deadlock on 20 minutes after Mouritz Botha went close to scoring, only to spill the ball under the weight of a tackle as he crashed over the line early on.
Instead it was Castres who grabbed the opening try through wing Paul Bonnefond. Captain and former England wing Philip Christopher beat three defenders in midfield before lock Rodrigo Capo Ortega put Bonnefond over in the corner. Full-back Thomas Bouquie converted.
The score was against the general run of play as the English club dominated the first half and three more penalties from the reliable boot of Jackson gave Saracens a deserved 12-7 lead by half-time.
However it was the French managing to score tries and they grabbed a second on 56 minutes. Replacement Yoann Audrin was first to react to a lose ball, catching Saracens short of numbers in defence by hacking up field three times before the collecting a fortuitous bounce to score.
Bouquie converted again to put Castres two points ahead however more home pressure forced the visitors into conceding another penalty deep inside their own territory.
Christophers was shown the yellow card, leaving Castres down to 14 men for the dramatic climax and Jackson swept home the kick before sealing victory with his sixth kick, five minutes from time.
Montpellier maintained the pressure on Pool Two leaders Connacht with a 42-6 victory at Olympus Rugby XV Madrid. No8 Giorgi Chkhiadze scored two of the French team's six tries in the bonus point win.
World Cup winner Francois Steyne scored the last of Racing Metro's eight tries as they regained second place in Pool 4, behind London Wasps, by beating Rugby Roma 53-3 in Italy.
The tie between Albi and Petrarca is scheduled to be played tomorrow (SUNDAY) after being postponed due to the weather.