Paris - Billy Burns upstaged older brother Freddie to lead Ulster to a gritty 22-15 victory over Bath on Saturday to secure a spot in the European Champions Cup quarter-finals.

Clermont ran out 26-19 winners over Harlequins to top Pool 3, on 24 points, with Ulster, on 21pts, qualifying as one of the three best second-placed teams.

Four-time champions Leinster will be top seeds in the quarters after making it six out of six for an unassailable 28 points to top Pool 1 with a 18-0 win over Treviso.

In Belfast, the battle of the Burns brothers went the way of Billy, whose sucessful move to Ulster has seen him picked for Ireland's Six Nations squad.

"We've got to be a lot better if we want to go further," Burns said.

"That's as tough a game as we've played here, all credit to Bath."

Burns added: "This group is hungry to learn and get better. I don't know who we'll be playing in the quarter-finals, but we'll look forward to getting stuck into it."

Springbok No 8 Marcell Coetzee opened the scoring for the home side, powering over from close range following an attacking line-out maul. In-form scrumhalf John Cooney booted the extras.

Bath drew level through Ruaridh McConnochie, the England winger pouncing on a Freddie Burns' cross-kick that evaded Jacob Stockdale on the bounce.

England cap Burns nailed the conversion.

Ulster kicked off the second period in perfect fashion, full-back Will Addison's smart offload setting Robert Baloucoune haring down his right wing for a try Cooney converted.

Burns senior clawed back three points with a penalty for Bath before Addison raced away for Ulster's third try following some slick midfield handling.

A Ross Batty pushover try for Bath set up what should have been a nail-biting final 10 minutes, but that petered out after referee Ruiz showed the replacement hooker a red card for a reckless shoulder charge into the face of Cooney, Burns hitting the penalty for Ulster.

Northampton kept their hopes of reaching the knock-out phase with a bonus-point 36-24 victory away at Lyon in Pool 1.

The Saints will, however, have to wait until Sunday's matches, where defending champions Saracens and Gloucester both have a chance to seal qualification, albeit with two tricky fixtures, at home to Racing 92 and away to Toulouse respectively.

Racing and Toulouse have already qualified, along with Clermont.

Pool 2 leaders Exeter, who have also qualified, play La Rochelle and Sale take on Glasgow in Saturday's late games.