Washington found Shildon too hot to handle as they slipped to a fifth successive defeat in Ebac Northern League Division One last night.
The Mechanics stayed three points clear of the drop zone as champions Shildon beat them for the third time this season.
Goals from Dan Parker, his first for the club, and Billy Greulich-Smith gave the Railwaymen a 2-0 lead after just eight minutes, and two more goals followed in the final six minutes of the first half, thanks to Lewis Wing, driving home a free-kick, and Daniel Moore, who earlier had an effort cleared off the line.
Washington keeper Dale Connor made a great save to deny Anthony Bell at 2-0, but went off injured minutes later.
Paul Connor’s 78th-minute goal finished the rout before the visitors had a man sent off.
South Shields are now just five points behind leaders North Shields after they won away 4-1 at West Allotment Celtic.
Jon Shaw’s 25-yarder into the top corner put the Mariners ahead, but Liam Hudson equalised right on half-time.
In the second half, it was all Shields and they regained the lead on 52 minutes with an own goal by John Pendlebury as he tried to deal with Anthony Callaghan’s cross.
The hosts had Dale Pearson red-carded for dissent and Shields capitalised to bag two more goals in the final eight minutes.
Julio Arca and Carl Finnigan combined to set up David Foley for 3-1, then Foley rounded keeper Chris Bannon to complete the scoring.
Newcastle Benfield comfortably beat Marske United 4-1 to leapfrog their opponents.
Paul Brayson bagged a hat-trick, with Jack Devlin also scoring, while Aaron Ramsbottom netted for Marske.
Bottom club Esh Winning secured a fantastic win in Division Two, 2-1 at sixth-top Hebburn Town.
Lee Best headed Esh in front, but Alan Pegram lobbed keeper Mark Fish to level just after the hour mark.
Two minutes later though, Shaun Ross rounded keeper Steve Hubery and scored from a tight angle to secure Esh’s surprise success.
Tow Law Town also won on their travels, 2-1 at Heaton Stannington.
Liam Dixon’s header and a fine Kieron Barker strike did the damage, either side of Dan Robinson’s reply.
Billingham Synthonia moved a point behind leaders Team Northumbria after beating Bedlington 2-1, courtesy of Anthony Peacock and Conor Winter. Lee Scott (penalty) replied.
Billingham Town routed Ryton and Crawcrook Albion 5-0, thanks to Elliott Beddow, Luke Hogan, Craig Hutchinson (2) and Connor Dunlavey.
Stockton Town beat Darlington RA 5-2, inspired by Kallum Hannah’s treble. Tom Coulthard’s diving header and a Kevin Hayes strike made it five. Callum Bennett, who opened the scoring, and Joe Peel, with a header, netted for RA.