Holders St Helens survived a ferocious battle with Hull KR to reach the Carnegie Challenge Cup semi-finals yet again on Sunday afternoon.

Saints, winners in the past two years and bidding to reach the last four for an eighth consecutive season, were tested to the limit by Justin Morgan's battling Rovers at Craven Park.

Ade Gardner's touchdown 10 minutes from time ultimately proved decisive as Saints won four tries to three but Rovers, who twice hit back to level, were aggrieved to have two further scores disallowed.

The hosts, and principally their new half-back combination of Paul Cooke and Michael Dobson, made a blistering start.

Cooke landed a 40-20 kick inside the opening minute and was then on hand to take full advantage from the resulting possession as he raced onto Dobson's delicate grubber to touch down.

Cooke landed the conversion and it could soon have got worse for Saints after Gardner spilled the ball and Dobson raced clear.

The Rovers attack broke down due to a forward pass but Dobson, making only his second appearance since arriving from Canberra, kept on the pressure by forcing Saints to drop-out from under the posts.

Yet, with Saints scrum-half Sean Long impressing with his range of passing, it was not all one-way traffic.

Lee Gilmour went close to a reply soon after Cooke's opener and Gardner, Super League's top tryscorer this season with 15, looked certain to score out wide but for another unfortunate fumble.

Saints pulled level after 14 minutes when Long cleverly reversed the direction of play and Gilmour sent Willie Talau over.

Maurie Fa'asavalu, moments after coming off the bench, then claimed a second as he took a Long pass and barged his way through the defence.

Long converted both but Saints were far from comfortable and were lucky to survive as referee Ashley Klein twice denied Rovers.

Shaun Briscoe and Ben Cockayne both thought they had scored but Klein spotted an obstruction in the build-up to the first and was unhappy with the grounding of the second.

Saints threatened to compound their misery as they pressed before the interval but Rovers broke from deep to claim the least they felt they deserved.

With just a minute remaining on the clock, Long shunned a drop goal opportunity to kick high to the corner.

Jake Webster came up with the ball for Rovers and he did enough to put Daniel Fitzhenry into a gap to race 80 metres to score.

Cooke's goal levelled the scores and Fitzhenry, Rovers' top tryscorer, almost had another early in the second half but the winger was unable to hold on.

Saints edged back ahead as Long's tricky run carried him to the line but Rovers could again feel aggrieved over the grounding, which had a hint of a double movement. Long looked far from concerned and got up to convert.

Rovers were not behind for long, however, as Paul Wellens missed Dobson's kick and Webster pounced, with Cooke again adding the extras to level.

Fa'asavalu was placed on report for a high tackle on Briscoe but Cooke was wide with his goal attempt from the resulting penalty.

Saints claimed the decisive try in the 70th minute after Talau found a gap and pushed close to the line.

Long was quick to join the action and spread the play wide with a fine pass and Gardner scored in the corner. Long maintained his 100 per cent goalkicking record to push the lead back to six.

The game was still not over as Chris Chester lost the ball over the line looking to bring Rovers back level yet again but Saints held on.