Bristol Bears 23-21 Saracens
Billy Vunipola booed as Saracens lose
England international Vunipola featured for the London club just a day after he controversially defended an anti-gay social media post from Israel Folau.
He was sent on after 50 minutes with Sarries 13-7 down and helped them reclaim the lead late on.
Ian Madigan, however, booted Bristol to victory with the last kick of the game.