Despite falling 2-0 and 3-1 behind, goals from Ollie Pearce, Omar Koroma, Mo Diallo and Danny Barker forced the tie into a shootout after the final whistle, which the home side won by four goals to two.
Leiston started the match brighter side and were rewarded in the ninth minute when a Roco Rees save from Matthew Richardson’s long distance drive fell to Liam Jackson who put the hosts 1-0 up.
Worthing struggled to carve out a clear-cut opportunity after the setback and were lucky not to go 2-0 down in the 26th minute when a Leiston cross found Jamie Eaton-Collins inside the six-yard box, but the striker placed his effort wide.
Eight minutes later, a Leiston corner was not cleared by Worthing, and fell to Jackson at the back post to score his and the Blues’ second.
In added-on time at the end of the half, Marvin Armstrong capitalised on a slip from Leiston left-back Ollie Saunders:
The midfielder then passed to Ollie Pearce, who drove into the area before rifling a shot which beat Sam Donkin at his near post to half Worthing’s deficit at the interval.
The Mackerel Men began the second half on the front foot and almost carved out an opportunity in the 48th minute when Jasper Pattenden drove into the area and found Ricky Aguiar, but the ball got trapped under his feet and Leiston eventually cleared.
Leiston then came close six minutes later when a promising move resulted in Richardson shooting from distance, but Rees comfortably saved his strike.
On the hour mark, the hosts restored their two-goal lead with a wonderful left-footed strike from Finlay Barnes which flew past Rees to make the score 3-1.
Ten minutes later, Worthing once again clawed themselves back into the game when a corner whipped in by Jesse Starkey landed at the feet of Omar Koroma, who bundled home in similar fashion to his winner at Potters Bar on Tuesday evening to reduce the deficit back to one.
The striker was also involved in Worthing’s equaliser five minutes later, when he latched onto a fantastic ball in from Joel Colbran:
His touch did not have the strength to cross the line, but substitute Mo Diallo was on hand to smash the ball into the net to put Worthing back on level terms.
Seven minutes later, a Leiston clearance created a foot-race between Barnes and Pattenden:
However, a mix-up in communication between the Worthing winger and the advancing Rees ended in Barnes retrieving the ball, before shooting it into an empty net to put Leiston 4-3 up.
With time seemingly running out, Aguiar led an attack for Worthing, selling Richardson a dummy before shooting from the edge of the area:
Although his effort was blocked, the ball fell into the path of Danny Barker, who slammed home to force the tie into a penalty shootout:
Koroma stepped up first for Worthing, but he placed his effort on to and over the bar, before Jackson scored for Leiston to give them the upper hand early on.
Colbran converted the next spot-kick for Worthing, as did Josh Hitter for Leiston.
The retuning Alfie Young scored Worthing third penalty, which was matched by an audacious “Panenka” from Leiston substitute Rob Eagle.
Dajon Golding then stepped up for the Mackerels, who placed his kick over the bar, before Barnes converted the instant sudden-death spot-kick to win the tie for Leiston.