WELWYN GC began the new year with their heaviest league defeat of the campaign so far, conceding five in a SSML game for the first time this season.
The Citizens also let in five when they met Southern League Div 1 Central leaders Royston in a Herts Senior Cup tie in November, but this was a much more alarming result.
It was Adam Fisher's side's only third loss in the league, but a costly one, as they failed to take advantage of a slip-up by long-time leaders London Colney in their Bank Holiday game at Leverstock Green.
Opponents St Mag's may have been lying fifth bottom going into this game, but are in a good run of form and this victory was their 10th successive match unbeaten.
They cruelly exposed an alarming lack of pace in the depleted WGC back-line for their main striker Harley Haag to score a hat-trick of almost identikit goals in the victory.
WGC were without the unavailable John McGrandles and the unwell Martin Standen in central defence and manager Fisher switched newcomer Louis Lee into the middle.
But the ex-Hitchin, Barton and Arlesey man had a torrid time alongside Yasin Boodhoo, as St Mag's soaked up WGC pressure and then hit the visitors constantly on the break.
The game began well enough for the Herns Lane side and they had the ball in the net in five minutes, Boodhoo spectacularly volleying home from a Ben Long throw, but the effort was ruled out on an assistant's flag, for an offence in the build-up.
WGC were struck a blow when they lost Emmanuel Melford-Rowe in 17 minutes following an injury on the far touchline. After lengthy treatment, the striker had to be replaced by Jack Read.
Josh Bronti fired WGC's first opening straight at home stand-in keeper Richard Hayward, before the Saints stung the Citizens with a 23rd minute opener. Ex-
Hatfield winger Chris Webb got around Jay Welsh on the right, centred across goal and Haag came in on the back post to slot past Jack Metcalfe, back in the WGC goal after a one match ban.
Five minutes from the break and with WGC on the attack, home full-back Simon Grove-White drove a 60 yard ball that found Attilla Korsovecki all on his own. With the WGC defence appealing for offside in vain, the St Mag's man was allowed to run clear, step around Metcalfe and roll in the home side's second.
There was a lengthy seven minutes of stoppage time following two serious injuries to St Margaretsbury players and during the overtime, WGC pulled one back.
Long got in a telling challenge on the edge of his own area and broke away to play a fine through ball to Read, who split the Saints' defence with an even better pass that put Bronti clear in the home area. He finished powerfully past Hayward for 2-1.
In the lengthy overtime, WGC really pressed and a move involving almost all their forwards and midfield ended with Sean Brettell slamming a left-foot effort against a post in the last action of the half.
The Citizens began the second-half in similiar vein and Hayward pulled off a good save from Bronti in the early minutes of the half, while Ashley Kersey took a chance set up by Brettell too wide and shot into the side netting.
But just before the hour. St Mags broke away for a third following a Brettell free-kick being blocked at the other end.
A long ball over the top sent home substitute Anthony Anstead streaking past a floundering Lee into the area for him to square the ball to Haag, again on the back post, for a carbon-copy goal to his first and 3-1.
WGC reduced arrears within five minutes. They forced a right-wing corner that produced an almighty scramble on the home goalline. Amid all the mayhem, Boodhoo bravely dived in to nod the ball over the line for an untidy WGC second.
But all hope of the Citizens battling back for a point were ended 10 minutes from the end, when again Korsovecki found himself in the clear down the left with the WGC defence trailing. He unselfishly squared his pass across goal and Anstead slotted home the fourth beyond Metcalfe.
To add insult to injury the Saints added a fifth three minutes from time, George Beattie getting the ball over from the right to find Haag again lurking on the back post. His low shot into the corner completed his hat-trick and WGC's misery.
WGC: Metcalfe, Griffith (Robins 66), Boodhoo, Lee, Welsh, Payne, Long, Brettell, Bronti, Kersey (Campbell 73), Melford-Rowe (Read 17).