The play-off bound Dons turned on the second half style to cruise into Tuesday's semi-final at Bromley.
It promised to be a nail-biting tense final day with attention too focused on the goings-on at Claremont Road. Any kind of slip up by Wimbledon was likely to pounced upon by Margate, who were expected to see off Hendon with minimum fuss.
But when is the last time football ran to a script' As Richard Jolly and co were finally finding their feet to shoot East Thurrock to shreds, the other Dons were keeping their side of the bargain and defeated the Kent outfit to make our passage into the play-offs that bit smoother.
And that was just as well if the first 44 minutes were anything to go by. Wimbledon struggled to get to grips with their already-safe opponents as the pressure of the edgy final day looked to be weighing on minds.
East Thurrock should have led after only five minutes. Lee Burns' cross wasn't dealt with and former Wimbledon midfielder Scott Curley lost his bearings and misdirected his unchallenged header. An early let off but that was the hosts' chance gone.
Three minutes later, the ever-impressive Roscoe Dsane twisted past and teased Wes Faulkner to pick out Luke Garrard. The Young Player of the Year couldn't match his striker's efforts with the finish it deserved - hitting his powerful shot right at keeper Jamie Riley.
But, after a poor start, a minute before half-time those nerves were settled. The quick thinking of Dsane paid dividends, spotting the run of Jolly who didn't need asking twice to rattle the ball beyond Riley to open the scoring at the most crucial of times.
And five minutes into the second half, a tonic arrived from elsewhere.
Belal Aiteouakrim had fired Hendon ahead against Margate - the odds on Wimbledon missing out of the top five had suddenly been slashed. But as word got round about Gate's blow, Wimbledon were securing their own destiny with a brutal spell of their own.
They should have gone 2-0 up when Riley got lucky after weakly parrying Dsane's free-kick onto the post. Then Jolly did manage to get the better of the East Thurrock goalkeeper - sliding his shot through Riley's legs to confirm the win beyond reasonable doubt.
And four minutes after, any lingering doubts were extinguished. Garrard's tasty free-kick was perfect for Lee O'Leary who nodded in his third goal in Wimbledon colours to add the gloss. With 20 minutes left on the clock there was no way back for East Thurrock - or now for Margate.
Garrard, back to his best after recent indifferent performances, wasn't content with only three and had his cross-cum-shot trickled in there wouldn't have been a wider smile inside Rookery Hill.
Also willing the ball into the back of the net was Steve Ferguson. But after his dainty footwork following Dsane's assist, he couldn't find the finish in a frustrating afternoon in front of goal for the former Woking man.
Garrard was next to tip-toe his way though a visibly tiring Rocks backline. This time no-one was there to sweep up but within minutes the fourth did arrive.
With the home defence all over the place, the ball eventually fell to the feet of Wes Daly who marked his best display of the season with the Dons' final goal of their league campaign. He wrapped his foot around the ball perfectly and found the net with confidence for only his fourth of the season.
If Dave Anderson's side can reproduce this final 46 minute-display on Tuesday night, Bromley - you have been warned.