The Hooks Lane outfit finished the season in style with a 68-33 win against London Cornish on home turf.
But second-placed Medway made no mistake – bagging a bonus-point win against bottom-of-the-table Gravesend.
It meant the Kent side maintained their two-point lead over Havant in the race to finish runner-up.
Will Knight admits it is galling to get so close again and not make it.
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The Havant head coach said: ‘It is gutting. At the start of the season our aim was to win promotion or a play-off place.
‘Ultimately, we haven’t achieved that and it was points dropped earlier in the season that eventually did for us.
‘In this league there is very little margin for error.
‘In other leagues at our level around the country, the second-place teams have lost seven or eight games. That wouldn’t be possible in London one south.
‘It shows that you have to be on it from day one and for pretty much the whole of the season.
‘We lost twice to eventual-winners CS Rugby and also lost narrowly at Medway.
‘In other games it was a case of if only.
‘Early in the season we lost at Chichester when we played most of the game with 14 men.
‘And at Brighton we should have won but didn’t. It is on those deep, dark midwinter days leagues are won and lost.’
Knight felt the response from the players on the final day was fantastic.
On a rock hard pitch as temperatures soared, they turned on the style to take London Cornish apart – scoring nine tries.
Cornish scored first but by half-time Havant had forged a 34-23 lead. Scott Morris, Richie Janes, Harrison Young and Tristan Trehan all scored.
Joel Knight added two penalties and four conversions and – after Cornish had offered brief resistence early in the second half – he kicked his third penalty.
From the 55th minute, the hosts put their foot on the pedal and pulled away.
Further tries were scored by Trehan, Nic Benjamin, Reuben Knight, Mitch Goldring and replacement scrum-half Wayne John.
‘The players were fairly upbeat at the end,’ added Will Knight.
‘They have the enthusiasm to push on again next season.
‘The drive and the ambition of the club to bring a higher level of rugby to the area remains the same.
‘It is important we sit down and learn the lessons from the last two seasons.
‘Maybe we will add a little bit more and change a few things on the coaching side.
‘We are all prepared to go again next season.’