Gadebridge FC have secured their place in the final of the Rous Cup after an extra-time goal by Alfie Mullan was all that divided themselves and Hadley B.
With the threat of penalties looming, Mullins struck to ensure a cup final clash with Vicarage Celtic.
Elsewhere, Hemel Rovers reached the West Herts Senior final after a superb extra-time performance at AFC Storm.
Olly Buckley and Paul Hanafan were on target for Rovers to ensure the game ended level after 90 minutes, before a brilliant 30-yard strike from full-back Jamal Babb put the visitors in front.
Buoyed by the goal, Rovers wrapped up the win in style as Ray Wood knocked in a hat-trick and Jordan Aikman completed the scoring to make it 7-2.
In the league, Kings Sports stretched their lead at the top of the Premier Division to seven points after Dan Tomkins earned a 1-0 success over Croxley C&H.
Tring Athletic A thumped Maple Cross 5-0 thanks to a Glen Sizer hat-trick and a double by Steve Wood, but Division One leaders Hemel Rovers Reserves were beaten 2-1 by Glenn Sports.
Bovingdon suffered a 6-3 home defeat to Tring Athletic B as Stephen Sandford (2), Richard Williams (2), Liam Hatter and Matt Miller struck for the visitors, while Potton End were beaten 3-0 at Oxhey Jets B.