Golds drew 3-3 with Newhaven to win the title by a point from Dorking Wanderers, who suffered an injury-time 2-1 defeat away to Arundel.
Littlehampton started the day ahead of Dorking on goal difference, so knew victory would seal the title.
Things did not go quite that smoothly, though, as Newhaven led 2-0 and 3-1 before Littlehampton fought back to make it 3-3.
News then filtered through to The Sportsfield that Arundel had scored three minutes into injury-time and, with two minutes of normal time still to play at Littlehampton, that was when Golds’ celebrations could begin, before the full-time whistle blew at both grounds shortly afterwards.
At exactly the same time, Golds fell behind to Newhaven and Dorking conceded at Arundel.
Newhaven substitute Brad Murray bundled the ball home from close range on 17 minutes while, at Mill Road, Scott Tipper crashed home a penalty to put Arundel 1-0- ahead on 18 minutes.
Littlehampton fell 2-0 behind when Adam Kneller curled home a superb 20-yard free kick, before Liam Humphreys got a goal back when he headed home Shay Wiggans’ inch-perfect cross at the back post on 37 minutes.
The half-time whistle blew with both Golds and Dorking losing, which meant Littlehampton would still be crowned champions if things stayed the same.
Newhaven increased their lead to go 3-1 ahead through Callum Conor on 55 minutes to increase the nervous feeling at The Sportsfield.
At Mill Road, Dorking levelled through Charlie Pitcher with 19 minutes to play to put them in pole position to lift the title.
Within seconds, Littlehampton got a goal back when substitute George Gaskin finished clinically from Dan Swain’s long ball over the Dorking defence to give Golds renewed hope.
With nine minutes to go at Littlehampton, Golds levelled from the penalty spot through George Landais after a foul on Joe Shelley.
Golds keeper Jon Hendrick made a superb one-on-one save to deny Conor on 88 minutes, before The Sportsfield quickly erupted when news came through that Arundel had gone 2-1 ahead.
Lewis Jenkins netted three minutes into injury-time at Mill Road and the final whistle blew shortly afterwards. There was still five minutes to play at Littlehampton but it was just a case of seeing out the time remaining, with Golds players fully aware that they were champions.