THE final scoreline of 36-20 may have flattered Saints in the end – and it was not their most complete performance of the year – but after having to dig deep they are in the last four of the Challenge Cup and that is all that counts.

Vikings played out of their skins for the first hour and deservedly led going into the final quarter after former Saint Chris Dean had nudged them in front.

It took a special effort, with Saints having to really dig deep to get themselves out of a hole, with Mose Masoe’s second stint essentially adding the weight to their pack’s battle to get on top of the Vikings’ six.

Masoe’s charge laid the platform for James Roby to shovel it wide for Kyle Amor to crash over for the try that broke Vikings’ hearts.

Jordan Turner powered over for the clincher and the game was already done and dusted by the time Mark Percival added the icing on the cake with a last minute touchdown.

It was a pulsating clash from the off and it took a try saving tackle from Jon Wilkin to stop Vikings drawing first blood when Kevin Brown dummied and dashed through before launching Alex Gerrard headlong to the line only to be stopped by the Saints skipper.

Saints opened the scoring on six minutes when Percival, Saints’ latest full back, collected Brown’s long, bouncing kick before shipping it on to flying wing Adam Swift.

The pacy wing backed himself, bamboozling the Vikings defence to go in and out before racing 90 metres for a classic try.

Vikings were quick to hit back, and they pressed the Saints line after Alex Gerrard’s powerful run had won a penalty.

Joe Mellor showed good strength and determination to force his ball-carrying arm over the line, with Danny Craven slotting the extras to level.

Percival slotted a penalty after Widnes were pinged for a flop, but Saints were out of sorts and the Vikings looked more than capable of cashing in, particularly with their pack getting on top and Kevin Brown pulling the strings.

However, somewhat against the run of play Saints extended their lead when Masoe’s offload unleashed the backline and neat interpassing on the left flank from Turner and Swift fashioned the opening for Percival to saunter over.

And after Vikings’ restart kick went out on the full Saints pressed forward with Matty Dawson crossing in space on the right. Percival missed the conversion, but Saints had somehow engineered a 18-6 lead.

Vikings were far from done and they poached something of a soft try when the determined Craven forced the ball over the line, with Patrick Ah Van’s conversion cutting the half time deficit to six points.

It was expected that the champions would get a half time rocket and come out in the second half more composed.

But it was the Vikings who took the game to the hosts with a powerful surge from big Welshaman Gil Dudson busting a gaping hole up the middle, with Percival coming a cropper when he finally halted him. Saints were still at sixes and sevens, and a man down, when the ball was shifted left for Ah Van to cross to cut Saints lead to two points.

Vikings’ tails were up and it looked as though Saints were hanging on and unable to stop what the underdogs were throwing at them.

There seemed a degree of inevitability about the Vikings next score – supplied by discarded Saints centre Dean. Although Craven missed the conversion, Vikings were suddenly in front for the first time.

Initially Saints’ response looked dull and there was definitely a case of them looking like a rabbit caught in the headlights of an oncoming car when Amor was caught in possession at first receiver on the last play of their next attacking set.

Although still in the arm wrestle, they desperately needed a game-changer and that arguably came with the weighty contribution of Masoe.

The re-introduction of Percival, passed fit after his earlier head knock, also gave the champions that little bit of a transfusion as they fought to keep their Wembley dream alive.

Fortunately Saints got a stroke of luck when Vikings were penalised for reefing the ball from Turner to give them a good attacking position.

Masoe launched his 19stone mass at the determined Vikings line and off the back of that momentum Amor was over, with a try given by the video ref despite the initial uncertainty from the man in the middle.

That drained something from the Vikings tank and this time Saints cashed in, like all ruthless teams dom with Turner bashing his way over on the left.

This time Saints’ tails were up, epitomised by the chase from Joe Greenwood and Josh Jones at the end, forcing Rhys Hanbury over the try line for a drop out.

In desperation the restart kick failed to go 10 metres allowing Percival to slot another penalty.

And it was the makeshift full back, playing against his hometown team, who dashed in for the last try just before the hooter to put a false reflection on the final score.

Saints are in the semis for the first time since their incredible run from 2001-2011 ended and that is all that matters.

But they know only too well that they will not get away with another display as careless as this, despite their flashes of brilliance and their ability to hang in and pull through late in the game.

Saints: Percival; Dawson, Jones, Turner, Swift; Burns, Walsh; Amor, Roby, Walmsley, Wilkin, Greenwood, McCarthy-Scarsbrook. Subs: Masoe, Flanagan, Richards, Savelio.

Widnes: Hanbury; Flynn, Marsh, Dean, Ah Van; Manuokafoa, Heremaia, Gerrard, Clarkson, Whitley, Leuluai. Subs: Cahill, Isa, Craven, Dudson.