Josh McCoy blazed 198 as Havant racked up an ECB Royal London national club championship best 420-9 against Ventnor to earn a place in the zone final.
McCoy, pictured, smashed 11 sixes and 22 fours, scoring 154 of his career-highest score in boundaries.
In all Havant, for whom Stuart Ransley hit 63 and Harry Gadd 32, breached the Steephill boundary 55 times as Ventnor used nine bowlers in a fruitless bid to halt the run surge.
Ventnor made 214 in reply, with Ben Duggan (45), Alex Horton (40), Hugh Calloway (40) and Martin Blackman (35) top scoring.
Spin pair Chris Morgan (4-25) and Stuart Ransley (3-61) took the bowling credits for Havant, who host South Wilts in the group final on June 19.
South Wilts have not had to bowl a single ball to reach the regional play-off – scheduled opponents Lymington crying off on Sunday morning due to being unable to raise a side.
Club official Neil Trestrail explained Lymington’s late decision to withdraw: “It's sadly quite simple: two players got injured on Saturday, one being Ryan Scott and when I got home from cricket on Saturday evening, I had two texts to say that two of our youngsters could not play, which left us with seven players, plus Stewart Hand (Dom’s father) left to play.
“We simply do not have a bank of reserve cricketers available to play cricket on a bank holiday weekend Sunday after a full league Saturday.
“Club cricket on Sunday's is dying a death, sadly this is a known fact and the National Knockout, no longer involves our strongest teams.”
South Wilts received a first round bye and then a walkover when Fawley conceded.