Wigan overcame a dismal start to outplay their oldest rivals and move to within two victories of an Old Trafford grand final.

Wigan overcame a dismal start to outplay their oldest rivals and move to within two victories of an Old Trafford grand final.

Saints were so much on top in the first half-hour that they must surely have thought they were on their way. But the impact of Luke Robinson from the Wigan bench and a gritty defensive effort from all his team-mates means that the season is over for Ian Millward and his team.

In the first significant action of a nervous opening passage of play, Mick Higham blocked Danny Orr's kick and set up a counter-attack that ended with Ian Hardman touching down. But the try was disallowed by the video referee for an accidental offside at the start of Higham's run.

Saints did take the lead after 12 minutes, however, when Craig Smith would not let Nick Fozzard play the ball and Sean Long put over the penalty.

The Wigan-born Long, in his second game back after his suspension for betting irregularities, was predictably booed every time he went near the ball, but he was part of a Saints side that was having distinctly the better of the first half.

Wigan's frustration showed in the number of penalties they were conceding and from another of them (for offside at the play-the-ball) Long kicked a further penalty. Yet another saw him make it a six-point gap as he continued to punish Wigan's indiscipline.

Saints would have been further ahead but for the try-saving tackle of Kris Radlinski on Higham after they had cut through the Wigan defence.

Wigan badly needed a spark of initiative and they got it from their substitute, Robinson, destined for Salford next season after Wigan decided he was not what they need. He showed all the cheek that a good half-back needs by taking a quick penalty near Saints' line, dummying to pass and diving over.

Andy Farrell kicked the equalising goal and Robinson was involved again as Wigan took the lead before half-time, instigating the attack that also included Adrian Lam and Gareth Hock before Kevin Brown plunged over, with Farrell adding the goal from the touchline.

Wigan's roll continued after the break with Sean O'Laughlin sweeping through Paul Sculthorpe's tackle and getting the ball away for his brother-in-law, Farrell, to score the try and convert once more.

Only a knock-on by Brett Dallas put an end to another Wigan try soon after. But Saints almost got back into the game when Long had a touchdown disallowed when he stole the ball from Brown's fingertips.

Saints were applying plenty of pressure but now they were the side lacking composure as Wigan's defence maintained its fierce intensity.

Saints finally got over for their only try of the match five minutes from the end, when Paul Wellens got an overhead pass away for Ade Gardner to score, Long keeping hopes alive with a touchline conversion. That guaranteed a nervous finish but with O'Laughlin making two crucial interceptions Wigan hung on to book their meeting with Wakefield next weekend.

Wigan: Radlinski, Dallas, Brown, Wild, Aspinwall, Orr, Lam, Farrell, Newton, Smith, Hock, Tickle, O'Loughlin. Subs: Robinson, Olly, D Sculthorpe, O'Connor.

St Helens: Wellens, Albert, Hooper, Talau, Hardman, Roby, Long, Fozzard, Higham, Cunningham, Gilmour, Joynt, P Sculthorpe. Subs: Gardner, Mason, Edmondson, Wilkin.

Referee: R Smith (Castleford).