Dover 0, Hastings 2.
Ten-man Hastings reached the final of the division one south play-offs with manager Nigel Cane declaring: "My players are all heroes."
United played just over an hour with a player short after Sam Adams saw red.
But two-goal Ade Olorunda ensured they went through to meet Tooting and Mitcham, who beat Fleet Town, away on Saturday.
Kane said: "No one else apart from our camp believed we could do it. We were the underdogs. Certainly some of their fans thought we didn't stand a chance.
"But we did our homework and it paid off for us.
"Sean Ray my captain was superb but they all were."
Every decent team needs a spine and Hastings had a strong one.
The home fans had stirred up Kane by insisting on their website the result was a "no brainer" because United had nothing that could threaten their side.
One Dover supporter before kick-off was overheard debating who he would prefer to face in the final.
But the claret and blue shirts were worn with pride by the visitors with Sean Ray and brothers Tim and Ade Olorunda epitomising their spirit.
Skipper Ray, in only his second appearance after returning from a three-match ban, was immense. The centre back had the Dover strike force in his back pocket and even cleared a James Dryden effort off the line as the hosts sought to fight their way back into the match.
Ahead Ade Olorunda put Hastings ahead after just ten minutes. He seized on a loose ball from the right and, with yards of space, side-stepped goalkeeper Glen Knight to fire into the roof of the net.
His strong running and physical presence was a constant headache to the athletic rearguard, while his brother Tim completed that strong spine by imposing himself on the midfield.
But Hastings suffered self inflicted wounds on 29 minutes when Adams was sent off for a second bookable offence.
The first yellow was an unnecessary and petulant offence when he kicked the ball away at a free-kick. But he saw red for for what seemed a minor foul on his opposite number Jon Wallis.
Hastings, instead of wilting with a man down, relished the challenge as Dover struggled to exploit their advantage.
Dover struck a post through Byron Walker in the first half but no one on the home side seemed capable of hitting the target after the interval.
With Dan Williams' endeavour and the pace of substitute Danny Ellis, Tim Olorunda had mighty support in midfield for Hastings and Lee Carey, although more subdued than usual, still managed to carve out two opportunities to extend the lead.
He latched on to a quick free-kick and forced Knight to save. Then his inswinging right wing corner looked to have provided Ray with a goal but the captain's header was tipped over by the goalkeeper.
But, ultimately, it was Knight who cost Dover the match. After his hesitation for the first goal he slipped up for the late second. He miskicked and presented the ball to Ellis and the substitute pulled it back for Ade Olorunda to thump home.
Dover boss Clive Walker said: "Hastings were strong and I think they can beat Tooting if they play to their strengths."
Dover Athletic: Knight; Browne, Rogers, Humphrey, Cloke, Wilkins (sub B.Spice 64), Wallis, Spiller, Dryden (sub Innocent 70), Tyne, Walker. Subs not used: Braithwaite, Lye, Smith.
Hastings United: Worgan; D. Spice, Elford, Whyborne, Ray, Williams, Adams, T. Olorunda, A. Olorunda, Rose (sub Ellis 53), Carey (sub Eldridge 79). Subs not used: Bradley, Cruttenden, Sims.
Referee: Mr E Smith (Surrey).
Attendance: 1,018.
Man-of-the-match: Ade Olorunda (Hastings).
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