Washington ended their five-match losing streak with three precious points from an impressive victory at Ashington.
But James Clark’s fourth-bottom side remain just a point above the drop zone as rivals Guisborough Town also won.
The Mechanics showed great character to bounce back from the previous weekend’s 10-1 drubbing from Sunderland RCA – and they raced into a 4-0 half-time lead.
Robbie Williamson put Washington ahead on 25 minutes, and eight minutes later Rhys Evans made it 2-0.
On 44 minutes, Evans scored his second and when Jake Pickard was brought down in the box, skipper Matthew Waters converted the penalty, to make it 4-0.
Although Ashington made a game of it in the second half, when Ryan McGorrigan and Ben Harmison cut the deficit by the 58th minute, Washington held out comfortably for three vital points.
They are back in action at Dunston UTS tomorrow.
Guisborough won 1-0 at West Allotment Celtic, who are now relegated alongside Chester-le-Street, to stay on the Mechanics’ tails.
Ryhope CW lost 3-1 at home to Newton Aycliffe in their penultimate match.
The visitors stormed ahead on 20 minutes, when Ben Wood scored from close range. Ryhope rallied and equalised in the 40th minute, when Danni Lay beat goalkeeper James Winter.
Aycliffe went back in front on 55 minutes, when Stuart Banks scored. Then, in the last minute, substitute Matthew Pennal added a killer third goal.
Seaham Red Star, playing their final match of the season, also lost 3-1 at home, to Morpeth Town, who are finishing the season very well and look good for a third-place finish.
Red Star took the lead though ,following a massive kick from goalkeeper Shaun Newbrook, which fell to Robbie Bird, who fired them in front after 14 minutes.
Three minutes later, Keith Graydon equalised from the penalty spot and Ben Sayer’s 25-yard shot screamed into the net to put Morpeth ahead on the half hour.
In the 35th minute, Graydon scored his second when he unleashed a 25-yard shot into the top corner.
Sunderland RCA went down 3-2 in a thriller at Marske United.
The hosts took a second-minute lead, when Aaron Ramsbottom fired home, and it was 2-0 on 11 minutes as Reece Kelly cut inside and fired home a low strike.
On 30 minutes, Colin Larkin missed a penalty for RCA, goalkeeper Robert Dean making a good save, and eight minutes later it was 3-0 when Danny Earl lobbed keeper Jonathan Carmichael from 30 yards.
However, on the stroke of half-time, Larkin’s cross found John Butler, who gave RCA a timely lift.
They got back to witiin a goal on 72 minutes when defender Greg Swansbury scored from close range, but the Seasiders held on for the three points.
South Shields will be playing in the Evo-Stik League First Division North next season, after a narrow 1-0 win at title rivals North Shields meant they achieved one of their season ambitions.
They also now head the table on goal difference, still with two games in hand on the Robins.
The all-important goal came in the 23rd minute as David Foley beat goalkeeper Kyle Hayes.
Julio Arca was sent off for a second yellow card shortly after half-time, but South Shields deservedly held on for the win.
Mariners joint manager Graham Fenton said: “If we win our next two games, I think we’ll become the Northern League champions.
“I’m delighted about getting our first aim of the season out of the way, which was to gain promotion, and this was a really tough game to achieve it in.
“Both sides had full commitment and the sending off almost changed the game, because we had to sit and defend and show big heart and character.
“We are obviously delighted with the whole team today and Julio’s sending off made it difficult for us, but you have to give massive credit to North Shields, not just today but the fight they have put up for the title this season, has been fantastic.
“It’s now 31 wins on the trot, but to the management team it’s just one game at a time for us.”
North Shields’ manager Jon McDonald said: “I thought it was a game of very few goal scoring opportunities. When South Shields went down to ten men, we got a little of momentum at that stage, but it never fell for us.
“We are disappointed with the result, but the message to the lads is that we have two games left and we owe it to ourselves and the club to finish strong.”
Consett beat Newcastle Benfield by 5-3 in an eight-goal thriller.
Benfield’s John Campbell opened the scoring in the ninth minute, but Danny Craggs equalised after 23 minutes.
The visitors went in front again a minute later, with Paul Brayson’s header, only for Michael Sweet to quickly level.
Benfield took the lead for the third time on 56 minutes, Joshua Scott firing home, but two goals in two minutes gave Consett a 4-3 lead. Mark Turnbull headed home in the 64th minute and Sweet struck his second.
In the 79th minute, Matty Slocombe made it 5-3 from close range.
West Auckland were well beaten, 4-0 at Whitley Bay. Kyle Patton hit a clinical hat-trick, with Peter Glen-Ravenhill adding a tap-in for 4-0.
Relegated Chester-le-Street lost 3-1 at home to Penrith.
Andrew Murray-Jones gave the visitors a second-minute lead and Martyn Coleman made it 2-0 after 51 minutes, but Chester fought back with Dominic Laws’ strike before Coleman sealed the visitors’ win.
Bishop Auckland and Dunston UTS played out a 1-1 draw.
Dunston went ahead in the 27th minute, when Dale Burrell’s header found the net. But sub Ryu Williamson levelled it up.
Fourth-top Shildon drew 1-1 at Jarrow Roofing. Billy Greulich-Smith had the Railwaymen in front with a shot from the edge of the area, but Chris Winn directed home a leveller from Dennis Knight’s free-kick.