Randall's score added to first-half tries from Jamie O'Callaghan, Matt Cook and Antonio Kaufusi as the Londoners made the last eight for the first time since 2007.

But it was a real nip-and-tuck affair at the home of the Championship side, with the game in doubt until the final seconds.

Rob Powell made a handful of changes ahead of the clash, with Michael Robertson and Michael Witt returning to the starting line-up.

There was also a first start for centre Michael Channing, after his replacement cameo at Hull KR last week.

The elements were all in place for an upset at Mount Pleasant, with driving wind and torrential rain throughout the contest.

But, after a tight opening, the Broncos broke the contest open with three tries in ten minutes.

O'Callaghan was first to cross on eight minutes, cashing in after a booming Craig Gower kick held up in the wind and deceived the Bulldogs defence.

And Gower was the provider again five minutes later, a neat pass allowing Cook to barge his way over.

Things got even better for the men from the capital when Kaufusi added the third try minutes later, smashing through three tacklers to rumble over at the sticks.

At that point things seemed fairly straightforward for the Broncos, but Batley had other ideas with tries from Danny Maun and Mark Applegarth hauling them right back into the contest.

The game swung to and fro after that, with muddied bodies struggling to gain any headway on a surface that cut up as the contest progressed.

It was real guts and glory stuff, and although the Bulldogs had plenty to offer, the Londoners were always able to hold them at arm's length.

Fully 45 minutes passed without a further score, but the visitors finally looked to have made the game safe ten minutes from time when Randall burrowed over at the posts, not long after a massive hit from Mark Bryant freed up possession.

The hosts still weren't finished though, Ian Preece pouncing on a kick through to once again drag Batley within a score, but the Broncos had enough about them to hold on.