Heading into the four-match home straight, leaders Hythe & Dibden and second placed Fareham & Crofton crashed to shock defeats against teams in the relegation zone.
Fast rising Parley lost six wickets for six runs before their last pair got them across the line against Alton.
As a consequence, Hythe’s lead is down to nine points over Parley, with Fareham now lagging 17 off top place.
Hursley Park and Ropley are now back in the promotion frame, albeit as outsiders.
Hythe were bundled out for 146 by Andover (171-9) while Fareham & Crofton were unable to defend 271-4 against United Services, who had lost all 11 previous games.
Steve Berryman (61), Tom Kent (51) and Luke Cornish, with a quick fire 57, looked to have batted Fareham into a winning position, especially when US dropped to 126-4.
But Josh Collighan smashed an unbeaten 87 and Sameen Mahboob 49 not out to take US home.
The match ended in controversy with Fareham unsuccessfully appealing for a late run-out – a player/umpire was standing at square-leg – and bowler Angus Southon storming off the field in protest, leaving his ten team-mates out on the pitch !
Ropley ran up 308-7 against St Cross Symondians III (185), while Hursley Park’s 218-6 proved too many for OTs & Romsey (186).
Parley appeared in comfort zone with fit-again Sam Collins (34) and Rosh Embalagama (27) taking them to 108-3 and in sight of Alton’s 127 all out.
But spinner Lee Partner (5-30) sparked a remarkable collapse, which saw Parley lose six wickets for only six runs – and creep over the line at 131-9 with their last pair at the crease.
Earlier, Jack Rowatt (5-32) had reduced Alton to 65-7 before the Brewers’ tail almost doubled the total.