Behind with less than four minutes to play, looking out on their feet through injuries, Haven scored two tries, both converted, with Dan Abram landing a superb touchline conversion after the hooter.
In the corresponding Easter derby at the Recreation Ground, Abram had landed a touchline conversion after the hooter to win it 14-12.
Whitehaven had been the better side in the first half to go in 10-4 ahead but the momentum seemed to be with Town in the second half as they came back to lead 22-12.
Haven had seemed to be beaten, with too many injuries, but they stirred themselves for one more effort and it paid off.
The first penalty of the game went Whitehaven’s way in the second minute to set-up their first set of six but Marc Shackley knocked-on early doors.
When they got it back for a second set, they got to the Town line where Perry Singleton took a kick through from Dion Aiye and kept the ball in play.
Whitehaven were setting the pace and Abram looked to be weaving through until he was stopped by Elliott Miller.
Workington got their first penalty on 11 minutes after Oliver Wilkes was held down in a tackle and, from 35 metres, Carl Forber was on target.
But Whitehaven responded two minutes later with a penalty of their own by Abram from 20 metres after he had been blocked chasing his own kick.
Town had the first real chance on 16 minutes after Jamie Doran’s kick through was gathered by Joe Hambley but, with little room to manoeuvre, he tapped the ball inside and Singleton could not hold on.
Typically, the tackling was fierce and competitive and, when the two sides got opportunity to kick at goal, they took them. Abram landed his second penalty on 18 minutes to edge Haven in front.
There was another chance for Town on 23 minutes after Carl Forster had been penalised for a late tackle on Andrew Dawson and this time Forber levelled the scores from just inside his own half.
The opening quarter had been an arm-wrestle, with little in the way of flowing rugby and the eighth penalty of the game on 26 minutes allowed Abram to give Haven the lead again from 10 metres.
The first try of the game came on 28 minutes after an amazing spell in which they kept the ball alive on last tackle, with the ball moved left to right.
Finally, a long ball from Stuart Howarth found Ellis Gillam on the wing and he dived in at the corner. Abram’s conversion attempt faded past the post.
Town responded well after Dave Thompson had dropped the ball and they built-up a promising move along the line until French centre Ilias Bergal knocked-on three metres out.
When Town came again, a good kick for the corner from Doran spelt danger but Thompson gathered well.
Two minutes before the break, Town were reduced to 12 men when Karl Olstrom was sin-binned for lashing out after the ball had gone.
Despite the handicap, Town were on the attack at the end of the half and Singleton’s kick on final tackle went dead.
Immediately on the resumption, Tyler Dickinson took out Callum Phillips after he had kicked the ball and Whitehaven were able to add to their lead with another Abram penalty.
Town then had a good spell with two penalties allowing them to retain possession deep inside Town territory but a little kick through was hacked dead by Jordan Burns.
On 51 minutes, it was Haven’s turn to play with 12 men when skipper Marc Shackley was sin-binned for a crusher tackle on Tom Curwen.
Town were able to make it pay four minutes later when they went close through Sean Penkywitcz and then moved the ball smartly left where Scott Rooke touched down in the corner. Forber converted from the touchline.
Shackley returned to a two-point game, but crucially, Haven had lost Dion Aiye to injury and he had been a key figure in defence.
Soon after, it was all-square when Forber kicked a short-range penalty and both sides had 18 minutes to find a winner.
But the momentum was with Town now, who were throwing the ball around much better and Haven seemed to be feeling the pace.
On 66 minutes, a smart break from Penkywitcz ended with a low pass out to the wing where Rooke took it superbly and scampered over in the corner. Forber was short with the kick.
A try on 73 minutes seemed to have settled it when Dickinson, who had been outstanding in the second half, charged over from eight metres with four defenders hanging on to him. Forber converted.
But brave Whitehaven weren’t finished and they responded magnificently to win the game.
Three minutes later, Gillam charged down Doran’s kick and followed up to gather and score. Abram’s conversion made it an interesting last three minutes.
Then, in the last-minute, Whitehaven levelled the score and a touchline conversion from Dan Abram won the game for them.
A kick on last tackle to the corner from Howarth was gathered by Danny Green who dived over for the try.
Then, in a repeat of the Easter derby at the Recreation Ground, Abram landed a fine touchline conversion to complete a League One double. Unbelievable stuff.
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