Saracens booked their place in the European Challenge Cup quarter-finals after a thrilling 40-33 victory over Cardiff at the StoneX Stadium.
The hosts were pushed all the way, but held out to secure the win, and will play Gloucester on the weekend of 7 May.
Dom Morris breached the Cardiff defence for the first try of the game on 36 minutes and Farrell’s conversion gave the home side a 10-point cushion.
But the Welsh side hit back on the stroke of half-time through Tomos Williams’ try and Priestland converted to reduce the deficit to 16-13 at the break.
Williams was then the chief architect for Owen Lane’s try in the 48th minute that saw Cardiff go ahead for the first time and Priestland added the extras to give them a four-point advantage at 20-16.
But Saracens rallied and a pair of tries from Sean Maitland and scores from Aled Davies and Max Malins saw them move into a comfortable lead.
Farrell added two conversions to put Saracens 40-26 up with 12 minutes remaining, with Priestland having kicked two more penalties.
Cardiff kept battling and Rhys Carre burrowed over late on with Jarrod Evans adding the conversion, but Sarries held on to secure their meeting with the Cherry and Whites.