Christmas came early for Spalding on Saturday with a deserved bonus-point win.
Having beaten Birstall at home in September, this was a first double of the season.
However, the outcome of the match went right to the final whistle with Birstall on Spalding’s five-metre line.
Just a couple of minutes earlier, trailing by two points, Spalding were searching for a vital break when a penalty was awarded to Birstall.
But indiscipline by the home team resulted in the decision being reversed.
Ashton Capes stepped up, having waited a few minutes while an injured player was treated, and from out wide the kick was slotted between the posts to win the match after the lead changed hands seven times.
Birstall started the match with plenty of confidence to put Spalding under pressure.
A penalty kick and a backs move from a scrum for the opening try established an eight-point lead.
Spalding gradually worked their way into the game and a break by Ash Piccaver led to George Brown being tackled off the ball and the outside centre was yellow-carded.
Spalding took advantage as scrum-half Ben Shields started a move and outside centre Gav Sharman broke through for an unconverted try.
Ten minutes later, again Sharman found space wide for his second try and a two-point lead.
Either side of half-time, Birstall looked to take control with two tries and a 10-point advantage.
Spalding were rocking but Jason Steels led the fightback with an outstanding display.
Captain Richard Cooke burst forward, only to be stopped just short of the try line, and Harry Cole was on hand to finish it off.
Sharman secured a hat-trick and Capes converted again for a one-point lead.
Spalding held on by the narrowest of margins to get the reward for a spirited team performance.