Northampton Saints were brought back down to earth after they suffered a 50-28 loss away to Champions Cup holders Bordeaux in a repeat of last season's final.
Bath lost a 26-point lead in an epic south-west derby only to snatch back victory in the most dramatic fashion in the closing seconds to beat Exeter 33-26, before Northampton Saints returned to the top of the Prem table.
Northampton stunned the Prem Rugby champions Bath with a devastating display of running rugby featuring a hat-trick of tries by freewheeling England back Tommy Freeman.
George Hendy's late try ensured a winning start for last season's beaten Investec Champions Cup finalists, Northampton Saints, as they saw off Pau 35-27.
Tommy Freeman ran in four tries as Northampton Saints fought back to defeat Saracens 43-31 in Gallagher Prem clash.
Gloucester slipped to a fourth successive Prem defeat of the season as west country rivals Bristol toppled them 49-34 at Kingsholm.
Former British and Irish Lions fly-half Ronan O'Gara has heaped praise on current Lion Fin Smith, saying: "It's actually scary how good he's going to be."
Tommy Freeman says Lions coach Andy Farrell has told the squad to "impress each other, not those on the outside" ahead of Friday's clash against Argentina, live on Sky.