The battle between two of the top four in Division One South of the Evo Stik Northern Premier Division finished goalless after 90 minutes.
The Tulips had the better of the first half, but couldn’t find a way past an inspired home goalkeeper at the Dog & Duck ground.
An ankle injury to Paul Walker meant Spalding played the final 10 minutes with 10 men, but they survived to force the shoot-out.
The teams converted their first five spot-kicks apiece, but Spalding’s Jordan Lemon saw his penalty saved enabling Diamonds to convert their sixth kick from former Tulip Jake Newman and move into the quarter-finals of the Evo Stik League Cup competition.
Most Popular
-
1
Darren Ferguson says Peterborough United lacked the ambition to stay in the Championship and he's staying patient while waiting for the right job opportunity to come along
-
2
Peterborough United linked with Ben Garrity as Port Vale boss seeks to play down link
-
3
Supercomputer predicts likely outcome for Plymouth Argyle v Peterborough United, Derby County v Barnsley, Sheffield Wednesday v Charlton Athletic, Bristol Rovers v Oxford United and every other League One fixture
-
4
Peterborough United should change their winning League One team!
-
5
Strong EFL Cup performance has given Peterborough United boss Grant McCann decisions to make ahead of Plymouth rematch
It’s the third season in a row Spalding have been knocked out of the competition after a penalty shoot out.