Waveney may have been missing a few players through injury and illness but they started on the front foot and put the Coleraine defence under early pressure with Blair Purdy and Travis McWilliams causing them problems.
Waveney took an early lead through a well struck Nico Dunlop free-kick from 25 yards.
Dunlop almost doubled Waveney’s lead with a shot on the turn before Coleraine equalised when Waveney failed to clear a corner.
Just before half time Camryn Millar struck the post and Blair Purdy forced the Coleraine keeper into another excellent save.
Jordan Barrow in the Waveney goal produced an excellent save to keep the score level by tipping a free-kick over the bar.
An excellent ball from Nico Dunlop released Joel Godfrey whose cross was just missed by the sliding Blair Purdy at the near post.
Waveney continued to create chances through Nico Dunlop and Camryn Millar but as the match looked destined for extra time Blair Purdy ran onto a through ball from Nico Dunlop and coolly slotted home at the far post to seal Waveney’s passage into the next round of the cup.
Man of the Match – Matthew Sheerin.
Waveney: P McMullan, C Millar, R Perkins, J Godfrey, J Barrow, N Dunlop, B Purdy, T McWilliams, A Dumbai, M Sheerin, C Bradshaw.