Bristol Bears pulled off a stunning fightback to beat Exeter Chiefs 20-17 and go top of the Premiership, while Waisake Naholo scored a debut try in London Irish's thrashing of bottom side Leicester Tigers on Sunday.

The Chiefs looked to be cruising to victory when they scored 17 unanswered points in the first half of a Sandy Park thriller.

Bristol had other ideas and snatched an unlikely win right at the end when Dan Thomas crashed over with Exeter unable to stop a driving maul.

Tries from Sam Simmonds and Nic White along with seven points from the boot of Joe Simmonds put Exeter in command at the interval, but Bristol scored 17 points in the last 20 minutes to stun Rob Baxter's side.

Callum Sheedy was on target with two penalties and Piers O'Conor dotted down with White in the sin bin before Thomas was awarded a decisive score following consultation with the TMO.

Sheedy added the extras as Bristol moved level with Northampton Saints on 14 points and replaced them at the summit.

Former New Zealand wing Naholo, one of a host of high-profile signings for the Exiles following their promotion from the Championship, was among five try-scorers in a bonus-point victory at the Madejski Stadium.

Nick Phipps picked out fellow debutant Naholo with a brilliant cross-field kick and the powerful flyer finished clinically, while Ruan Botha was another new recruit to touch down to keep the Tigers at the foot of the table.