The early clashes were brutal. Shuddering tackles by both back rows, quality recycling and handling splashed with nervy niggle and errors. Twice in the opening quarter of an hour the referee, Steve Lander, was obliged to speak to warring players before edginess made way for focused foraging.
Two premier back rows with Richter-scale tackle counts coupled with pacy backs who gradually got their game together, and the front fives did their stuff as well. There was a stream of possession for both sides, but it was the leaders, Wasps, who got the ball rolling with a long-range Gareth Rees penalty.
Moments later, when Andy Lee had an attempted kick charged down by the alert Nick Greenstock, Saracens were in more trouble. Some neat interplay with his fellow centre Rob Henderson resulted in Kenny Logan darting in for a simple try, the first of his two, converted by Rees.
When Lee failed to convert Tony Diprose's 20th minute try, a miss compounded by Sheasby's sharply taken pick-up and dive over following a series of scrums on the home line, things looked bleak for Saracens. Rees's third successful kick had provided a 12-point lead.
It took Saracens until injury time before they managed to take some of the stuffing out of that cushion. Lee having finally found the mark with a 33rd minute penalty, the packed Enfield ground was dragged roaring into half-time when the England flanker Richard Hill launched a counter-attack with a clever inside pass to full-back Matt Singer. The former South African captain Francois Pienaar thundered up in support of Richard Wallace, took the ball on before recycling it in the tackle to hooker Greg Botterman, who left Lee with a simple conversion from under the posts and the gap was two points.
There was more thrust than cut in the third quarter. Some superb defence by Saracens, including a number of notable tackles by scrum-half Kyran Bracken (no doubt taking out his anger and frustration at his rejection by the Lions) saw Wasps kept at bay and allowed the home side to counter.
Unfortunately they could not avoid conceding a penalty and Rees kicked his fourth out of four. Back the determined Saracens came and in a thrilling five minute spell they were awarded a couple of penalties close to the Wasps line. But the position was wasted when they went to ground once too often and Wasps flew clear.
That was revealed to be a criminal waste when the ever reliable boot of Rees was able to punish Saracens for transgressing offside well within the Canadian full-back's range. How Saracens miss their kicking machine Michael Lynagh, sidelined by a badly bruised hip. He expects to be back against Sale on Tuesday but his return will surely be too late for the north London side.
But if they missed Lynagh, Saracens need a finisher in the class of Logan. He wrapped the game up with just seven minutes remaining, bursting through the flagging opposition lines for his second try to help Wasps to open up a five-point lead at the top of the Courage League, having inflicted on Saracens their first home defeat of the season.
Saracens: M Singer; M Ebongalame, P Sella, S Ravenscroft, R Wallace; A Lee, K Bracken; T Daly, G Botterman, A Olver, P Johns (C Yandell, 73), T Copsey, F Pienaar, T Diprose (capt), R Hill.
Wasps: G Rees; S Roiser, N Greenstock, R Henderson, K Logan; A King, A Gomarsall, D Molloy, S Mitchell (K Dunn, 73), W Green, M Greenwood (D Cronin, 73), A Reed, L Dallaglio (capt), C Sheasby, B White.
Referee: S Lander (Liverpool)