A fine comeback in which they registered two converted tries in the last nine minutes revived Wasps' title ambitions, which had been dealt a blow by London Irish's victory at the Madejski Stadium.
However, if Wasps were determined on revenge it did not show in an incompetent first-half performance.
Wasps huffed and puffed to no great effect each time they crossed the Irish 22, either spilling the ball in contact or failing to outflank the opposition's drift defence because of predictable passing. The uncompromising hardness of the Exiles' tackling meant Wasps had to use brain as well as brawn to score a try.
Irish also revelled in the perfect surface which encouraged their wings, Paul Sackey and Nmandi Ezulike to embarrass their markers with a bewildering turn of pace.
With 10 minutes gone Sackey, a tall elegant Londoner with an eye for the Wasps' line, scored a thrilling try, gliding past three defenders, including his opposite number Paul Sampson, before grounding the ball in the right corner.
That opportunist score, supplemented by Barry Everitt's touch-line conversion plus an earlier penalty, put the Exiles 10-3 ahead though Kenny Logan quickly reduced the deficit with his second long-range penalty. Irish made basic errors in ruck and tackle situations that enabled Wasps to stay in the hunt thanks to Logan's cool marksmanship on a windless evening.
Nevertheless, the Exiles were 13-6 up midway through the half courtesy of Everitt who found the target with an astonishing penalty from half way that saw the ball still rising as it flew over the crossbar. Everitt demonstrated his versatility with a third penalty which was stroked home with an angled chip kick from wide out on the right before Logan responded with his third penalty from a similar position. The Irish were good value for their 16-9 half-time lead.
Wasps continued to claw their way back through the dependable Logan, who kicked another excellent penalty for offside shortly after the break to close the gap to four points.
Another penalty kick from Logan in the 68th minute left his side just one point adrift, and with nine minutes to go hooker Trevor Leota put Wasps in the lead after diving on the ball to score a try which Logan converted.
Three minutes later Paul Sampson chased through and leapt onto the ball after it left the boot of Mark Denney. Logan once more converted to complete a fine comeback.
Wasps: Lewsey; Sampson, Waters, Denny, Logan; King, Wood; Molloy, Leota, Green, Reed, Shaw, J Worsley, Volley, Dallaglio (capt).
London Irish: Cunningham; Sackey, Oliver, Appleford, Ezulike; Everitt, Tonu'u (capt); M Worsley, Alexopoulos, Hardwick, Fahrensohn, Williams, Halvey, Danaher, Sheasby.
Referee: S Leyshon (Bristol).
