Havant finished their London One south campaign with a rollercoaster 35-35 draw against Cobham at Hooks Lane.
The home side led for most of the game but were pegged back by their relegation-battling visitors deep into stoppage-time.
‘It was a frustrating game for us in many ways,’ said Havant coach Will Knight.
‘At times we played some fantastic running rugby to score some good tries.
‘On the other hand we fell off too many of our tackles and kept allowing them back into the game.
‘The game had an end of season feel and some of our players weren’t up for it enough.
‘We were clearly the better side but let ourselves down through poor defending.’
Cobham opened up with an early penalty but a Ben Brierley try and two tries from wing-forward Mike Brook put Havant in charge.
The visitors grabbed their first try but a reply from Grant Morris gave the home side a 24-13 lead at half-time.
Jake Reynolds extended the lead with a penalty immediately after the restart.
Disastrously, though, the home side fell asleep for 10 minutes during which the visitors scored two tries and, at 27-25, were right back in the game.
The topsy-turvy affair continued with Havant winger Ed Wilks squeezing over in the corner for a try and Reynolds adding another penalty.
The hosts were leading 35-25 going into the dying stages but Cobham made them pay for their carelessness with a penalty and converted try to snatch a draw at the death.
‘Give Cobham credit they are fighting for their lives and kept coming at us,’ said Knight.
‘We took our foot off the gas and they punished us.’
Havant Colts are through to the final of the National Plate after beating Dartfordians 22-20 in a thrilling semi-final.
Tom Gwyther kicked the winning points late on to set up a final against Wharfedale.
Petersfield suffered a 30-17 defeat at lowly Farnborough in their final Hampshire One game of the season.
The Penns Place side will be happy with a mid-table finish in their first season back in the senior county division.