Munster gave themselves a chance of topping their Heineken Cup group after a clinical away victory over Castres.
Castres 9 (9)
Pens: Marticorena 3
Munster 46 (13)
Tries: M Horan, S Payne, J Kelly, P O'Connell 2, T O'Leary 2
Cons: O'Gara 3, J Manning
First-half tries from Marcus Horan and Shaun Payne put Munster in charge, but two injury-time penalties brought Castres back to 13-9 at half-time.
But Munster cut loose after the break, with John Kelly, Paul O'Connell (2) and Tomas O'Leary (2) all crossing for tries, securing a vital bonus point.
The win brings Munster level on points with Sale, who they face next week.
Sale have a game in hand, playing the Dragons on Sunday.
The winners of each of the six groups go through automatically to the quarter-finals, joined by the two best-placed runner-up teams.
Munster's powerful pack laid the foundations for their backs to play an expansive game as they blew Castres away in the second half.
Laurent Marticorena and Ronan O'Gara exchanged early penalties, and it took Munster until the 32nd-minute to make their all-round superiority really tell when Horan muscled his way over after a series of drives.
Soon after Payne went over on the left following some slick handling among both forwards and backs.
Two more Marticorena penalties cut Munster's lead and suggested a tricky second half in store for Declan Kidney's men.
But an explosive start to the second period put them in the ascendancy, and the visitors never looked back.
Kelly was put over just two minutes into the action after a clever O'Gara kick through, and soon after the influential Paul O'Connell barged his way over for the try that brought up the bonus point.
It was plain sailing for Munster from then on, as O'Connell crossed again.
O'Gara then handed O'Leary his first try on a plate, as the fly-half intercepted a loose pass and sprinted to within two yards of the Castres try-line before giving the scoring pass as he was tackled.
And with Castres heads dropping, O'Leary's support running was rewarded as he grabbed another late score to add further gloss to the scoreline.
Castres: Christophers, Milford, Raffault, Tuilagi, Fleming, Marticorena, Barrau, Hoeft, Romieu, Attoub, Ghezal, Capo, Puricelli, Froment, Taussac. Replacements: Vigneaux, Castex, Spanghero, Bernad, Volley, Fior, Teulet.
Munster: Payne, Kelly, B. Murphy, Halstead, Dowling, O'Gara, Stringer, Horan, Flannery, Hayes, O'Callaghan, O'Connell, Leamy, Wallace, Foley. Replacements: Fogarty, Pucciariello, O'Driscoll, S. Keogh, O'Leary, Manning, Connolly.
Referee: Chris White (RFU)