Chichester were worthy 18-13 winners of a vital National three London south east game at home to Dorking thanks to their very strong team performance in the first half.
This gave them a ten-point lead and although mid-table Dorking pressed later, they were unable to catch up.
Chi avenged their 38-33 defeat in the away fixture last September.
Blues are now just four points behind Southend in their determined effort to pull out of the relegation area.
Chi were without Jack Maslen but Aaron Davies, Nick Blount and Richard Adams returned. Ben Deavall moved across to tight head prop.
They kicked off in bright but cold conditions. A Jak Evans kick was followed and forwards and backs combined in good phases.
This week brings another must-win game at Sutton and Epsom, who are in good form and won a big game at Colchester.
Aaron Davies sprang and delivered from the lineout to start a big drive by the pack, loose-head prop Tauisi Vadei pressing down at the right corner. The conversion fell short but it was 5-0 after four minutes.
Henry Anscombe kicked long to touch but Dorking countered with a kick and chase by their quick left winger Osborne.
Chi launched two attacks, the first stopped by a Dorking intercept knock-on but the second a flowing move across the backs which Evans finished off with a ten-metre dash and cut inside to score. A missed conversion left the score 10-0 afte ten minutes.
Dorking reached the home 22 for the first time but Chi cleared. A big touch kick by Adams set up more attacks and it looked as though the visitors were already buckling, with Chris Johnson, Aaron Davies and Taff Davies all breaking tackles.
The visitors went offside to foil a chance and Taff Davies slotted the penalty.
Another drive lineout just failed with the ball lost almost on the try line. Jack Bentall climbed high to give the backs another run as Chi emphasised their edge in the set-pieces.
Two penalties against Chi in scrum and ruck stirred Dorking into action, but Chi stole a lineout. The visitors advanced to the left corner but were held up. As they switched direction, Alex Grace tackled powerfully.
Dorking captain and playmaker Matt Noble put an accurate kick to the right wing but Anscombe and Evans helped each other to scramble clear.
The Surrey men were now fully awake and Chi conceded a penalty, converted by Noble. It was 13-3 at the break.
Dorking drove to the right flank, Chi were penalised for entering the maul from the side and Noble converted well to make it 13-6. But he narrowly missed another penalty for a high tackle.
Chi almost paid dearly for trying a quick lineout which went wrong but they held firm. They returned to the attack with Sam Renwick and Matt Woodhouse making a lot of ground. A move shifted from the right to give a scrum in the centre.
When the ball emerged hooker Mark Giddings looped around the back line to take a pass and accelerate from 25 metres. He broke one tackle and rode two others to crash over at the left corner for a superb try. The conversion was missed but the lead was 18-6.
Replacements were on as Dorking upped their game again and Chi had to defend at full stretch for several minutes, but they finally won a turnover to huge cheers from their supporters, Danny Gray clearing to touch.
Chi went to the other end and applied their own pressure, Dorking tackling hard. A yellow card was awarded harshly to the mighty Johnson for a high tackle under the new RFU rules.
Dorking began a fast counter-attack which went along very close to the left touch with some clever inter-passing and resulted in a try from the final inside step. The conversion by Noble was good and it was 18-13.
Dorking were in with a chance of nicking it but Chi held on in the last few minutes despite giving away penalties, in the end winning a turnover and scrum for Gray to kick out.
This week brings another must-win game at Sutton and Epsom, who are in good form and won a big game at Colchester. Chi won the home game against them 15-13.All support welcome for a 3pm start.
Chichester: Vadei, Giddings, Deavall, Blount, A Davies, Grace, Bentall, Johnson, Anscombe, Adams, Woodhouse, T Davies, Renwick, Seaman. Reps: Evans, Belcher, Dickin, Gray.
Don’t miss out on all the latest breaking sports news where you live.
Here are four ways you can be sure you’ll be among the first to know what’s going on.
1 Make this website your homepage
2 Like our Facebook page at facebook.com/pages/Sport-Sussex
3 Follow us on Twitter @SportSussex
4 Register with us by clicking on ‘sign in’ (top right corner). You can then receive our daily newsletter AND add your point of view to stories that you read here.
Share with your family and friends - so they don’t miss out!