It took an injury-time try, his third of the match, by Emile Ntamack, one of 13 internationals in the Toulouse side, to break the deadlock after Jon Callard, the Bath captain, had kicked his sixth penalty to level the scores at 25-25 in the 77th minute.
Andy Robinson, the Bath coach, had preferred his right- hand man Callard to the England full-back Matt Perry and the decision was almost vindicated. Almost but not quite.
In the end, though, it all went horribly wrong for the West Country club, who were outscored by four tries to one against a team whose pedigree is every bit as rich, if not richer, than Bath's. Toulouse possessed too much power, pace, experience and nous and above all, they had in Ntamack sheer class. The wing, fresh from playing a part in France's heroics in the World Cup, is a one-off.
Unusually tall, he is deceptively languid, as indeed were Toulouse themselves for much of this match. Ntamack who, like a giraffe, looks as if he has been designed by committee, scored a try in the first half and two more in the second and it was his effort shortly after half-time that really compromised Robinson's decision to favour the old head of Callard over the young legs of Perry.
With Bath leading 15-12, the French forwards launched a huge drive deep into enemy territory and when the ball was moved right, Ntamack ran on to a clever pass from the former All Black Lee Stensness to sever the Bath defence. Although he had an overlap on his right, Ntamack elected to beat the last line of defence, Callard, which he did with embarrassing ease. It was cordon bleu against roast beef and two veg.
To their credit, Bath took the game to Toulouse in the second half and re-established the lead with a superb try of their own. From a line-out inside their own half, Mike Catt sent Kevin Maggs through the middle of the French defence with a beautifully timed pass and the Ireland international threequarter had the pace to sprint 55 yards.
Callard's conversion put Bath ahead 22-19. Two penalties by Michel Marfaing to one by Callard had it 25-25, but as the game moved into injury time, Ntamack, almost inevitably, had the last word.
The opportunity to Toulouse was presented by the unfortunate Catt, whose kicking throughout had left a lot to be desired. In the 42nd minute, an attempted clearance was charged down by the impressive No 8, Sylvain Dispagne, who hacked the ball on into the Bath 22. When it was recycled to the right, Fabien Pelous found himself in the centre and he threw out a long pass to Ntamack, who strolled over, or at least seemed to stroll over, in the corner. It was probably no more than Toulouse deserved, despite their penchant for conceding a stream of penalties.
The first half was evenly matched between Callard's boot and the more rounded performance of the French. Bath were indebted not just to their experienced full-back but to the Irish referee, David McHugh, who penalised Toulouse almost every time he looked at them.
After missing his first kick at goal in the opening minutes, Callard, one of only three survivors from the side who so memorably won the European Cup in Bordeaux two seasons ago, put Bath ahead in the 12th minute.
However, the home side knew exactly what they were in for when Toulouse struck seven minutes later with the first try of the match. After the Bath forwards had squandered possession, Toulouse moved smartly and swiftly to the right where Cedric Desbrosse slipped an inside pass to Ntamack and although he was tackled a yard short of the line by Shaun Berne, he athletically managed to touch the ball down.
Back came Bath in what was proving to be a traditional style. Callard landed penalties in the 26th, 30th and 34th minutes to give his side a 12-5 lead and all the awards were given for the French falling offside.
By contrast, Toulouse found it easier to score tries and two minutes before the interval they drew level. After wasting an enormous overlap on the right, they managed to regain possession and when they switched direction, Franck Belot found himself in acres of space and his path to Marfaing put the left wing over. Marfaing converted his own try, but with the last kick of the half Callard landed his fifth penalty to put Bath 15-12 ahead.
Bath's best chance of opening their European campaign with a vital home victory came 14 minutes from the end when a number of miss-moves confused the Toulouse defence, but unfortunately Tokunbo Adebayo, a half-time replacement, knocked the ball on with the line at his mercy. Such chances were few and far between and ultimately Bath were forced to recognise that they had been out-manoeuvred and out-classed, particularly by the elegant Ntamack.
Bath: J Callard (capt); I Balshaw, S Berne, M Tindall (T Adebayo, 40), K Maggs; M Catt, G Cooper; C Boyd, M Regan (A Long, 68), C Horsman (G Mallet, 71), W Waugh, S Borthwick, A Gardiner (G Thomas, 68), B Sturnham, B Clarke.
Toulouse: S Ougier; E Ntamack, C Desbrosse,, L Stensness, M Marfaing; A Penaud, J Cazalbou; C Soulette, Y Bru, F Tournaire (L Esposito, 61), F Belot (capt, H Miorin, 64), F Pelous, D Lacroix, S Dispagne, C Labit (J Bouilhou, 77)
Referee: D McHugh (Irl)