Holders St Helens withstood a tremendous display from struggling neighbours Warrington in an energy-sapping Carnegie Challenge Cup quarter-final to reach the last four for the seventh year in a row.

The Wolves made a mockery of their dismal League form to lead 12-4 at half-time and remained on course for their first win at Knowsley Road for 13 years until Great Britain second rower Lee Gilmour scored his second try of the match on the hour.

After scoring five tries to two, Saints were worthy winners but they almost paid a heavy price for the lack of a specialist goalkicker, with Sean Long and Paul Wellens missing four conversions between them in the absence of Paul Sculthorpe.

Already without five regulars through injury, Warrington lost Great Britain international Adrian Morley in the first minute after he came off worst from a clash with Saints prop Nick Fozzard.

He came back after an hour, shortly after Saints had retaken the lead, but was unable to prevent his side going down to an eighth defeat in their last 10 matches which keeps the pressure on coach Paul Cullen.

The game looked to be going to form when Gilmour profited from a kind bounce to cross for the first try after just 57 seconds.

And, as the holders piled on the pressure, stand-off Leon Pryce was brought down short by a trysaving tackle by Paul Johnson, centre Willie Talau was held up over the line and Jason Cayless and James Roby both had tries disallowed before half-time.

Like a seasoned boxer, Warrington took the punches and hauled themselves off the ropes to land a few telling counter blows, with two tries in four minutes.

First 19-year-old winger Kevin Penny produced a classic finish, demonstrating searing pace to go around Ade Gardner and claim his third try in just three senior appearances.

Lee Briers landed the touchline conversion to edge his side in front and the Wolves extended their lead almost straight away, despite their influential captain down having treatment at the time.

Michael Sullivan and Brent Grose worked the ball out wide where Henry Fa'afili made amends for an earlier missed chance to cross for a second try and Briers again added the tricky conversion to make it 12-4.

Warrington had let slip a 12-6 lead against Saints in their League derby a fortnight earlier and the anticipated fightback began within two minutes of the resumption when left winger Francis Meli palmed the ball back back from Long's high kick for Willie Talau to touch down.

Wellens took over the goalkicking after Long failed to convert Gilmour's opening try but he had no better joy and was also off target when right winger Ade Gardner took advantage of a big overlap to score Saints' third try on 49 minutes.

That left the scores tied at 12-12 but Briers restored his side's lead with a penalty after the home side were pulled up for obstruction inside their own 20-metre area.

Saints made life difficult for themselves with a series of errors but they came up with another classic handling move on the hour to go back in front.

Wellens, Jon Wilkin and Long kept the ball alive in typical Saints fashion for Gilmour to cut through for his second try and this time he touched close enough to the posts to make Wellens' conversion a formality.

That might have been the signal for Warrington to concede defeat but they continued to play with admirable spirit and Penny had a try disallowed for a forward pass.

But Saints finished well on top and, after Wellens, with a penalty, and Long, with a drop goal, had put some distance between the sides, substitute James Roby clinched victory with a late solo try.