Fabien Galthié admits Montpellier took a major step forward by claiming their first away win in the Heineken Cup - but he rued their failure to seal a try-scoring bonus-point.
The French club kept their European hopes alive in Pool Six with a 35-24 victory over Cardiff Blues.
Yoan Audrin, Mamuka Gorgodze and Timoci Nagusa all crossed for tries but they were unable to grab a crucial fourth despite playing against 14-men for 55 minutes of the encounter.
The victory sees Galthié's men move to second in the pool, trailing French rivals Toulon by five points.
"For us it was a very big result - it's Montpellier's second year in the Heineken Cup and this is the first time we have won away from home," said the former France scrum-half.
"We still have the chance to qualify but it would have been better if we got the bonus-point.
"One try was disallowed for a forward pass and we came close at the end. That would have been enough to get the extra point but it is still a very big day for Montpellier."
The dismissal of Williams for a tip-tackle on Benoit Paillaugue proved to be the turning point in the hard-fought encounter but Galthié was in no doubt that John Lacey made the correct decision.
"It was a dangerous tackle that deserved a red card," said Galthié.
"The law is the law. The red card was important, it changed the face of the game."
Montpellier welcome the Blues to Stade Yves du Manoir on Saturday and back-to-back wins would enhance their chances of qualification.
But Galthié, who made 36 European appearances, reckons his side have already exceeded expectations.
"Everything we have done for the last two and a half seasons, is well above our targets. We exceed our goals. We can hardly do better, but you can easily do worse."
