LAST season's finalists the Linnets, using a young side, came from behind to maintain their excellent recent record in this competition.
Lynn have not been beaten outside the semi-finals since 1998. They also managed their first away win of the season.
As well as the win, the most pleasing thing for manager Peter Morris must be the performances of striker Mark Ward, who scored on his debut, and his reserve players.
Also on target were Robbie Harris, making his first team debut, and Jack Defty, making his first senior appearance of the campaign. Nicky Blake impressed down the left.
Morris said: "All the youngsters did well, and did not let anyone down. Jack Redhead would have played had he not gone down with flu.
"He should be involved in the next two or three weeks."
"Jack got on to the pace and physical side of the game and looked more than comfortable."
On new man Ward, he added: "In the second half he improved, got more in the game, held the ball up well and knows where the goal is.
"I didn't get to meet him until a quarter-to-seven.
"Ninety minutes isn't enough to see what he's made of, so we need to get him in training over the next 10 days."
Morris left on the bench both ex-Spalding striker Lee Stephenson on his return to the Sir Halley Stewart Field and keeper Dean
Greygoose, starting with youngsters Chris Bacon up front and Tom Dobrowolski in goal.
Dobrowolski endured a nightmare opening half, giving the Tulips their first chance in the 17th minute when trying to be too clever with a clearance, which Paul Goodhand returned with a lob that went inches over the bar.
Jamie Lawrence did not capitalise on another mistake, but as Lynn failed to clear their lines the hosts earned a free-kick which Goodhand expertly curled into the top corner on 23 minutes to give Dobrowolski no chance.
Dobrowolski did well to keep out another special from Goodhand, who seems to be the Beckham of the Fens.
The Walks outfit picked up their game after this and levelled just three minutes later after skipper Glen Fuff had volleyed over a cross.
Robbie Greetham pulled Defty in the home box, and debutant Ward - who displayed good vision in the tie confidently stuck away the resulting penalty into the bottom corner.
Good work by Defty on the right set up Ward, who was unlucky to see his drive acrobatically pushed around the post by Brett
Reserve teamer Harris came on at the break and was lively as Lynn sealed the tie with two goals in a minute.
After 67 minutes Ward played the ball through to Harris, who took it round the keeper on the right of the box and fired past two despairing defenders from an acute angle. He celebrated with a double somersault.
Then Defty used his strength to head in a centre off the underside of the bar at the far post.
Spalding came back late in the game and Matt Stinson, sub Peter Taylor and Lee Sowerby spurned good chances, Taylor the worst culprit when the ball stuck under his foot a yard from goal!
Morris added of Harris' goal: "It was very brave. Robbie needs a bit more strength, and he's not to be rushed."
Lynn: Dobrowolski, Staff, Blake, Burrows, Fuff, Cowling, Weston (Holmes h-t),
Raynor, Ward, Bacon (Harris h-t), Defty. Subs not used: St henson, Anderson,
SpaIding: B. Chittock, S Walton, M. Huggins, D. Cundy, R. Greetham, K. Jones, J. Lawrence (P Taylor 34), P
Goodhand, M: Stinson, S. Dennis (B. Lewsam h-t), L. Sowerby. Not used: D. Elding, A. Irvine, P Bryant.
Att: 169. Referee: A. Barks (Peterborough).