The Hawks clinched promotion to the National League for the first time in their history in the most dramatic fashion.
An 88th-minute goal from Jason Prior took them to a 3-2 win against Concord Rangers and the National League South title.
It proved an emotional rollercoaster at a packed Westleigh Park as the Hawks went desperately close to blowing their chances.
At half-time the hosts were coasting to the title – holding a 2-0 lead and in total charge.
That all changed after the break when two Concord goals levelled the scores.
With Dartford winning at Bognor, it meant the Hawks were off the top and staring the play-offs in the face.
That remained the situation for nine agonising minutes until Prior knocked in the all-important winner.
Lee Bradbury admitted he thought the Hawks had thrown their chance away.
The boss said: ‘I thought it was slipping away from us. The last seven or eight minutes were agonising.
‘We just had to go for it and thankfully we came through.
‘In the technical area we experienced every emotion possible – from joy to despair and back to joy again.
‘It looked comfortable until the first Concord goal went in.
‘Then all of a sudden we looked nervous and a bit leggy.
‘When they scored a second we had to throw everyone forward because we knew we had to win.
‘At that stage I thought we would either win it or lose it.
‘In the end Jason did what he has been doing for us all season.’
It all looked plain sailing for the Hawks when they went in at the break two goals to the good.
On nine minutes, Theo Lewis got on the end of a Brian Stock free-kick to put the Hawks ahead. A deserved second arrived on 26 minutes with Matt Tubbs knocking in Bradley Tarbuck’s low cross at the far post.
From the 52nd minute, however, the mood changed when the Beachboys pulled a goal back.
A crowd of more than 2,000 were silenced on 80 minutes when a deflection off Jordan Rose gave the visitors their second.
The finish was nerve-shredding until Prior provided the final blow in what has been a thrilling title race.
Relegated Bognor bid farewell to the division with a 2-1 defeat against Dartford at Nyewood Lane.
The Rocks were looking to do the Hawks a favour by upsetting the Kent side – who trailed Bradbury’s men on goal difference alone before the final day.
But after a goalless first half, Dartford took a 59th-minute lead and added a second on 77 minutes. Ollie Pearce scored a late consolation for Bognor.
Hawks: Young, Rose, Woodford, Harris, Tarbuck, Fogden (Carter, 90min), Stock (Hayter, 81min), Lewis, Williams, Prior, Tubbs (Rutherford, 64min). Att: 2,270