Defending champions Toulouse were indebted to Fijian winger Timoci Matanavou and giant Tongan forward Edwin Maka for sealing their French Top 14 season-opening 23-22 win over Castres on Friday.
The 19-time champions were trailing 22-18 with nine minutes left when they snatched victory at home in a bad-tempered match played in sweltering conditions.
Maka released fellow replacement Matanavou with a sharp pass and the winger dived in for his side's only try of the night, the score allowed to stand despite a hint of a forward pass.
"I am particularly proud of the mental strength of my players," said Toulouse coach Guy Noves.
"Once again when we were in difficulty, and up against it at the end of the match, but we found the resources to get through. It's a win that undoubtedly will be very important later."
Castres coach Laurent Labit admitted his team has a lot to learn.
"Each year we get closer, but don't do enough to get past," said Labit.
"It came down to just a few little details. We made too many mistakes and showed a little indiscipline that allowed Toulouse to stay in touch."
Castres, beaten 24-15 by Toulouse in the semi-finals last season, had trailed 15-9 at the interval with Lionel Beauxis and Castres's South African scrum-half Ryan Kockott kicking all of their sides' points.
But having reduced the deficit to 15-12 with another penalty early in the second half, Kockott then put Castres in front with a clever individual try after 52 minutes.
Picking up from the back of a ruck, Kockott sprinted 30 metres and through three tackles to score for a 17-15 lead which then became 19-15 with a successful conversion.
Both sides were reduced to 14 men when Toulouse flanker Jean Bouilhou and Castres replacement fly-half Pierre Bernard were both sin-binned for dangerous tackles.
With Beauxis off the field, former All Black Luke McAlister took over the kicking duties for the champions and he cut the deficit to 18-19 with a penalty.
Kockott, who scored all of Castres' 22 points, replied with his fifth penalty of the evening to restore his side's four-point lead.
But that was the cue for Matanavou's late try for a 23-22 advantage.
McAlister missed the conversion while Toulouse then had to hang on grimly when lock forward Gregory Lamboly was yellow-carded five minutes from time for another dangerous tackle.