The visit of the league leaders and fellow promotion contenders Northern was the perfect time for a big performance and West duly put in by far their best of the season in a resounding win.
It was impressive on both sides of the ball - the defence was terrific and holding the free-scoring visitors to three tries, one in stoppage time at the end of the game, was a great effort.
In attack, West looked after the ball well and forwards and backs carried with purpose and power - Alex Barker a standout performer in the forwards and Will Hilditch lively in the backs.
West dominated the first 10 minutes with the visitors under immediate pressure thanks to some of that hard carrying and ball retention.
Fly half Stu Waites kicked a couple of penalties to the corner but the Northern defence held on and when Andrew Rollins lost the ball reaching for line it looked like the hosts might come away empty handed.
But undeterred, they kept pressing and a high tackle from Harrison Clarke allowed Waites to again kick for the corner and this time the rolling maul got across the line, Adam Brown emerging as the scorer.
Northern responded well with a period of pressure but a turnover from a scrum in West’s 22 would lead to a second score.
Peter Youll made an initial bust upfield before releasing Will Hilditch and then Adam Peacock who was stopped deep in Northern territory.
As West advanced towards the line on the right, the ball was then slickly moved along the back line for Max Tennant to finish off a fantastic team try.
Waites added the conversion for a 12-0 lead with a little over 20 minutes played.
The league leaders had scored at least four tries in every game this season so their scoring threat was clear and they pulled one back through full-back Elliott Trott and then continued to test the home defence in the 22 in the final stages of the half.
West came away only having conceded a penalty to Ali Gray thanks to intensity and commitment in defence.
Leading 12-8 at the break, the game seemed predictably poised for a nail-biting conclusion.
West were first to strike in the second half with Stu Waites using penalty advantage to throw a long pass to Adam Peacock who nicely rounded his opposite number for a try in the right corner, with Waites adding the tough conversion.
But again Northern bounced straight back with two long breaks setting up enough space for dangerous runner Louie Tang to outpace the defence and get a deserved try, converted by Gray.
A crucial moment in the game came after 18 minutes of the half with a chip ahead caught cleanly by Northern but referee Les Cash waving away claims of a mark being called and allowing the West defenders to drive the visitors back over their own line to win a 5 metre scrum.
West had been dominating the scrums and another big effort drove the Northern pack back allowing replacement Scott Butcher to score the all-important fourth try.
Another scrum close to the line almost produced a carbon copy score,but the defence held out a few more phases until Brown powered over for his second from short range to finally give home supporters some breathing space at 31-15 with 17 minutes to play.
Content on pinning Northern back inside their own half for the closing stages, West rounded off their scoring on the back of another scrum, this time Ryan Painter taking advantage of a two-on-one to sell a dummy and run in unopposed.
Northern added a try in injury time and a quick drop-goal conversion allowed time for the restart and possibility of their trademark bonus point try - but the ball was lost from the kick and the final whistle blown.
The five-point swing tightens things up at the top of DN1 with Northern remaining top but Durham City now only two behind and West a further point back.
West: Southern, Tennant, Hilditch, Youll, Peacock, Waites, R Painter, Coates, Rollins, Cookland, Bunter, Atkins, Barker, Robinson, Brown. Reps: Butcher, Rafferty, Johnston
Tries: Brown 2, Tennant, Peacock, Butcher, Painter
Cons: Waites 3, Southern
Northern: Trott, Reah, Young, Appleby-Rutter, Tang, Clarke, Gray, Hirst, Mullick, Douglas, Kell, White, Kay, Smallwood, Burt. Reps: Liley, Matthews, Wilson
Tries: Trott, Tang, Liley
Con: Gray, Clarke. Pen: Gray. YC: Clarke
Referee: Les Cash [Durham Society].