English champions Bath got the defence of their Prem title off to the best possible start with a 47-31 bonus point win at Harlequins on Friday.
Bath trailed 17-14 at the break as Quins got off to a flyer with flanker Will Evans scoring a hat-trick of tries inside 30 minutes.
But two tries on debut from new signing Henry Arundell helped to turn the game upside down as Bath ran away with it in the second half.
Bath scored seven tries in total, with hooker Tom Dunn and prop Billy Sela crossing in the first half, with fellow prop Beno Obano, Archie Griffin and Sam Underhill adding to Arundell's tries in the second half.
In Friday's other game, Owen Farrell's Saracens upset a new-look Newcastle with a 39-17 victory in the north-east.
Last month, Newcastle were taken over by Austria-based energy drinks company Red Bull, and the side showed they had new wings when Alex Hearle crossed for the first try in the opening minute.
Saracens, though, recovered to lead 15-10 at half-time following tries from Brandon Jackson and Andy Onyeama-Christie.
Nick Tompkins scored twice in the second half, and 18-year-old debutant wing Noah Caluori also touched down to seal the win and secure the bonus point.
Farrell marked his return to the Saracens line-up with 12 points off the boot.
Thursday's opening game saw Sale defeat Gloucester, while the remainder of the opening round will be played on Sunday so as to avoid any clashes on Saturday with the Women's World Cup final between England and Canada at Twickenham.