Broncos head coach Rob Powell admitted that his side were in a no-win situation. "You win by a lot and people will say that the opposition was poor, we're a Super League team and they aren't," he said. "All you can do is focus on what we did and I thought we played pretty well today. I thought we defended strongly with a good mental attitude."

With Championship club Featherstone Rovers having caused an upset 24 hours earlier by beating Super League neighbours Castleford, the Broncos couldn't afford to take Dewsbury lightly. But, given that the Rams coach Warren Jowitt had rested some of his more experienced players and fielded a very young side, it turned out to be a desperately one-sided contest.

However, the visitors made a lively start to the game with a promising move down the left breaking down just metres short of the Broncos line. But it was the home side who struck first when a penalty gave them good field position and Antonio Kaufusi, taking a short pass from Chris Bailey, proved unstoppable to score under the posts.

Michael Witt added the conversion and minutes later Kieran Dixon leapt high to take a Craig Gower bomb before touching down in the corner. The Rams tightened up their defence and made life difficult for the Broncos but after 21 minutes Chad Randall found a way through, scooting over from dummy half after they had forced a goal line drop out.

Witt made it 16-0 with the conversion and minutes later he was on target again to convert a superb individual effort from Dan Sarginson. The centre then became try maker, providing the pass for Dixon's second touchdown following a slick passing move along the back line.

Dewsbury went close to opening their account when big centre Andy Smith was hauled down just short of the line. Matthew Tebb then forced his way over from dummy half but couldn't ground the ball. That was to be as close as they came to scoring for a long time.

Just before the break, the home side increased their lead with Luke Dorn sidestepping his way through and Witt's fourth conversion making it 32-0.

The home side struck again immediately after the interval, Jamie O'Callaghan going over after good work from Witt. The stand off then converted his own touchdown as the Dewsbury defence began to wilt dramatically under the constant pressure and it was now a question of how many points the Broncos would rack up before the final whistle.

Chris Bailey and Kaufusi added further converted tries but going into the final quarter the Rams finally got points on the board when a flowing move ended with winger Jamaine Akidere crossing in the corner. But normal service was resumed when the Broncos launched an attack from deep in their own half which was finished off by Witt.

However the stand off suffered a leg injury in the process and was subsequently replaced after Gower converted the touchdown. Gower was again on target when Matt Cook crashed over and O'Callaghan collected his second to wrap things up.

Powell is in no doubt about the importance of the Challenge Cup saying: "I think it gives you the opportunity to get some momentum. A good cup run gives the fans something to get excited about and the players something to get excited about, you only need to put a couple of wins together and you're in the semi-finals.

"It's a long time since this club has had a good cup run and if we can start building some momentum, I think people will be excited about that. Nine out of our 19-man squad today was London people. They care about playing in a Challenge Cup and if you speak to any of the Australian guys they know how important Challenge Cups are."

The fifth round draw will take place on Monday at 3pm in Leeds and be broadcast live on BBC radio. The ties will be played over the weekend of April 27-29.