Ramsgate's Ryman League Division 1 South status is in their own hands after a 3-1 home win over Carshalton on Saturday.
Simon Halsey's Ramsgate side remain in the drop zone but are now just a point behind Hastings with a game in hand.
Warren Schulz gave Rams a 10th-minute lead but Tommy Bradfield equalised 10 minutes later. Aaron Quain restored Ramsgate's advantage five minutes before the break and Tom Chapman added a third early in the second half.
Sittingbourne are now mathematically safe after Harry Smith and sub Adam Williams scored twice in two minutes late on at Chipstead.
Steff Joseph put Chipstead ahead midway through the first half but Williams equalised in the 86th minute before Smith scored the winner a minute later to ensure Nick Davis' side will be playing Ryman League football again next term.
Hythe could yet claim a top-half finish after Michael Yianni's 21st-minute goal was enough to claim an excellent 1-0 win at Guernsey. Ian Pulman's goal proved just a consolation as Whitstable went down 2-1 at home to Corinthian Casuals.
Faversham and Folkestone remain neck and neck in the race to finish second.
Faversham currently hold that position on goals scored as both have an identical plus-56 goal difference. Town beat Horsham 2-0 thanks to goals in either half from Dean Grant and Matt Bourne while Folkestone saw off Redhill 2-0 with second-half goals from Ian Draycott and Richard Atkins.
In Division 1 North, Chatham inched closer to safety with a vital 2-0 home win over Barkingside. The win leaves Chats four points outside the drop zone with two matches left to play.
Kieron McCann put Kevin Watson's men ahead on 26 minutes and Joe Bingham added a second with 17 minutes left.
Cray Wanderers moved out of the relegation zone with a 4-2 win at Brightlingsea Regent, their seventh successive victory.
Phil Kelly put the hosts ahead before Alex Teniola's brace made it 2-1 to Cray, who then had Chris Piper sent off in the 37th minute. Adrian Stone made it 3-1 with two minutes left before Jake Gordan replied for Brightlingsea only for Cesc Fakinos to wrap up the points for Tommy Warrilow's men.
Thamesmead went down 2-1 at Romford despite Bude Anidugbe's second-half goal.
Tonbridge Angels moved another step closer to safety in the Premier Division with a 3-0 home win over Witham, who now look doomed.
Angels are three points above the drop zone with two games to play after Marvin Williams' 14th-minute opener was added to by Billy Medlock on the stroke of half-time and then from the penalty spot just after the hour mark.
VCD are out of the drop zone after a 2-0 home win over Wingate & Finchley. Michael Power put them ahead on 11 minutes and then wrapped up the points with a late spot-kick. They visit Margate before hosting Billericay on the final day of the season.