Munster's Thomond Park fortress remains unbreached after Declan Kidney's men sent Castres home to France without a point.

Munster have never lost a Heineken Cup match at Thomond Park - despite 21 matches there - and they weren't about to begin last night. The perennial Cup playoff attendees led 19-13 at halftime, despite playing into a swirling wind, and cruised to an impressive 26-point victory.

It was a much-needed victory after a heavy first-round loss to Sale Sharks, and Munster can travel to the struggling Newport Gwent Dragons in December confident of another five points.

British and Irish Lions outside-half Ronan O'Gara controlled the game beautifully from fly-half, and the 14 points from his boot kept the home side in front throughout.

Fellow Lion Donncha O'Callaghan was driven over the try-line in the opening minutes, and things looked ominous for the visitors. Laurent Marticorena pegged back some lost ground with two penalty goals, but the famous Munster maul was soon in the action again as it carried hooker Jerry Flannery over the line for their second try.

Winger Anthony Horgan made it three before Castres hit back through impressive outside-half Romain Teulet, but the French side had the wind at their backs for the first half and they were never going to overturn a 19-13 deficit at the break.

Marticorena and Ronan O'Gara (two) swapped penalties as the weather worsened, and Munster confirmed their bonus point in the 64th minute when winger John Kelly collected a pinpoint O'Gara cross-kick to score. O'Gara converted from the touchline to make it 32-16 and seal the victory.

Inside centre Trevor Halstead used his power and pace to add Munster's fifth try, and the home side could even afford to lose winger Shaun Payne to the sinbin without conceding any points. In fact, their defence in the final 10 minutes was just as effective as their attack in the first 70 minutes.