They led 14-6 at the interval courtesy of a try from scrum-half Ben Spencer — who Stringer replaced in the 56th minute — and Farrell’s first three penalties before Biarritz came back at them in the second half.
Dimitri Yachvili scored all of the points for Biarritz, including a charge-down try off a Stringer box-kick, as the French visitors pushed Saracens to the wire and earned a losing bonus point.
But Saracens now need only gain a single point against Treviso next weekend to confirm their place in the last eight.
Meanwhile, Danny Care put his off-field issues to one side yesterday to play a key role as Harlequins kept their Heineken Cup ambitions alive with a 20-14 victory over Gloucester.
Harlequins were facing elimination when Care — who will appear at Southampton Magistrate’s Court today to face a charge of drink driving — saw his kick from the outside of his right foot bounced awkwardly for Gloucester wing Charlie Sharples and allowed Mike Brown to score the decisive try.
“He’s been playing really well recently. He is obviously hurting inside but he doesn’t let people see that — and that is good for the team because he doesn’t want to drag people down,” said Brown.
“That is why he is such a good player to have around. He is a big leader for us. It shows what a character he is to bounce back. He is reacting positively.”
Cardiff Blues coach Gareth Baber was pleased with his side’s focus as they moved a giant step closer to quarter-final qualification.
The Welsh side marked their 100th Heineken Cup match with a tight 22-15 victory at London Irish, with Sam Warburton’s second-half try complementing a fine Leigh Halfpenny kicking display.
Having seen fellow Pool Two pace-setters Edinburgh win away to Racing Metro on Friday, the Welsh side responded in the perfect manner at the Madejski Stadium and backs coach Baber was proud of his side’s attitude.
“The game (on Friday) did focus the mind somewhat,” he said after the match. “You can’t avoid it but our whole focus this week has been making sure we control what we are doing, irrespective what is happening outside of our environment.
“That extended to last night and what happened in Paris so we’re pleased we kept that focus. We certainly kept it through the game today and came away with the victory.”
Cardiff face Racing Metro in the final Pool Two match next weekend as they look to reach the knockout stages for the first time since the 2008-09 season.
The Blues are well placed after yesterday’s result, which saw them complete the double against the Exiles after winning the reverse fixture in November.
In Ulster’s Pool 4, Clermont ran in 12 tries to thrash Italian whipping boys Aironi 82-0 at Stadio Brianteo on Saturday to keep alive hopes of a place in the quarter-finals.
The French side raced ahead with some early scores and were already 47-0 in front at the break.
Wingers Sitiveni Sivivatu and Julien Malzieu completed their hat-tricks in the second half, with Brock James kicking seven conversions to add to four from Morgan Parr.
Full-back Lee Byrne scored a brace, while Alexandre Lapandry, James and Elvis Vermeulen also touched down as the French side collected a bonus point ahead of next weekend’s home clash with pool leaders Ulster.
Bath’s disappointing Heineken Cup campaign continued as they slumped to their fourth defeat in five matches, going down 24-22 to Montpellier thanks to a last-gasp try.
Bath had looked set for victory as two tries from lock Ryan Caldwell helped put them 22-17 ahead going into the final minute, but Montpellier snatched their first-ever Heineken Cup win when Timoci Nagusa went over for a score that was converted by Martin Bustos Moyano.