With the try count 6-5 in Saracens’ favour, it was Farrell’s unblemished 27-point haul that really made the difference after Dai Young’s swashbuckling underdogs had burst into life, having trailed 30-5 early in the second half.
A relentless display by the home pack underpinned a victory that secures a place in next Saturday’s final at Twickenham, but once the game had opened up it was Wasps who set pulses racing.
The defensive shortcomings that have plagued Wasps throughout the season surfaced as early as the second minute as Farrell slipped between Ben Harris and Joe Launchbury before sending Alex Lozowski over. But there was nothing spectacular about the second try as a series of drives ended when Vincent Kock barrelled over.
Willie le Roux started and finished a Wasps try that also involved Nathan Hughes and Christian Wade, but it merely served as a brief interruption to Saracens’ dominance.
Chris Wyles dived over in the left corner shortly after half-time, but Wasps then sprang into life when Jake Cooper-Woolley powered across the whitewash a minute later.
A wonderful pass by Danny Cipriani released Wade on the loop and the former England wing sprinted into space before finding Thomas Young, who finished under the posts.
Farrell’s fourth and fifth penalties settled Saracens’ nerves, but Wasps remained lethal as Cipriani and Guy Thompson combined to put in Le Roux. The favourites then threw off the shackles as Schalk Brits and Sean Maitland made ground for Juan Figallo to score.
Maro Itoje and Wade exchanged late tries before Saracens’ replacement scrum-half Ben Spencer completed the rout.