Simon Yeo, scorer of two late goals for Lincoln City in the first leg of the Nationwide Division Three play-off semi final on Saturday, added a third at Scunthorpe to send the Red Imps to the final against Bournemouth.
For much of the game Scunthorpe, facing a two-goal deficit, battered away at the Lincoln rearguard, but were unable to breach it.
And it took an 88th minute strike from Yeo to settle the nerves of the City fans who had roared their team on with great fervour.
"The lads have come on leaps and bounds," Lincoln boss Keith Alexander said after the game.
"We have made a few people happy. No-one expected us to be so successful this season, but we have the best defence in the third division." Scunthorpe boss Brian Laws commented: "We played with a lot of passion and I couldn't have asked for more from my players.
"The damage was done at Lincoln but we should view the season as a success, having reached the play-off stage." Scunthorpe set their stall out from the start and dictated most of the first half.
They were soon on the attack and rookie striker Paul Hayes made a fine run before driving the ball across for Paul Dalglish and it needed a fine covering tackle from Paul Morgan to halt his progress.
Matt Sparrow then forced Andy Marriott into two good stops, the second being tipped over by the keeper.
In a rare attack Richard Butcher fired a volley straight at Tommy Evans from 35 yards.
But Scunthorpe were soon back in control and Wayne Graves, a 26th minute substitute for Ian Kilford, broke through to fire a left-foot shot at the keeper.
Hayes lifted the ball over the top as the home side maintained their impetus and Dalglish struck a free-kick which was inches wide to the keeper's right hand.
City did have the ball in the net just before the break through Butcher, but he was ruled offside.
Scunthorpe initially laid siege to the Imps goal, but the visitors repelled everything thrown at them and replied with Mark Bailey hitting a 25-yard free-kick wide of the mark.
Sparrow then went close for Scunthorpe with a shot when put through by Dalglish and Andy Dawson saw a free-kick deflected wide.
However, as the game drifted away from Scunthorpe, the Imps struck an 88th minute body blow when Yeo found himself with space to score the winner on the night and give his side a commanding 6-3 aggregate win.