Leinster will be at home to Biarritz in the quarter-finals of the Heineken Cup after the Irish side defeated the Shoguns in front of the Bristol club's biggest crowd of the season.

Bristol made one change from the side that won 30-22 away to Monferrand with England wing Phil Christophers returning after a rib injury. The 22-year-old replaced Brendon Daniel who scored two tries in France but is sidelined for eight weeks with a broken thumb.

Full-back Girvan Dempsey returned to the Leinster side so Gordon D'Arcy switched back to his normal right-wing spot with David Quinlan dropping to the bench.

Leinster had already qualified for the quarter-finals but needed a win to secure a home tie and avoid a repeat of last season when they slipped-up in the final pool game against Toulouse.

The Shoguns went into this game harbouring an outside chance of qualifying for the last eight as one of the two best runners-up. But to achieve that they knew that they had to win and score nine tries or eight tries with a 45-point winning margin.

Bristol applied the early pressure but were unable to breach the Lions line and it was the visitors who scored the first try. Aidan McCullen took the ball from the line-out and powered over the Shoguns defence to touch down.

Scrum-half Brian O'Meara added the conversion from out on the left but missed a second five minutes later from the other side of the field after Lions' centre Brian O'Driscoll held off a tackle from lock Alex Brown.

The Shoguns finally got on the scoreboard as fly-half Felipe Contepomi gave a long pass out to former All Black centre Daryl Gibson. Another long pass went out to the wing for Christophers to squeeze in the corner but Contepomi failed his his conversion attempt.

Both sides had to reorganise their back line with Dempsey and Christophers limping off on the half-hour. Denis Hickie reverted to full back with Quinlan going to the wing while Martin Shaw went to the left wing for the home side.

The Shoguns, seemingly more interested in attack than defence, let the Lions through for a third try as centre Shane Horgan pounced on a chip from fly-half Shane Warner but O'Meara again missed the conversion from out on the right.

The Lions were reduced to 14 men just before the interval when McCullen was sent to the sin-bin by Welsh referee Nigel Owens for persistent offside. Bristol took advantage of the extra man to score their second try five minutes into time added on.

Right wing David Rees took a long pass from Gibson to score in the left corner with Contepomi converting from the touchline. But it was Leinster who went into the break 17-12 in front with the Shoguns looking for seven tries in the second half.

Rees looked set to score his second try shortly after the restart but was bundled into touch just short of the line. The Shoguns then made another good break involving Gibson, Andrew Higgins, Brown, Agustin Pichot but hooker Paul Johnstone out wide lacked support.

Contepomi was yellow carded for hands in the ruck and O'Meara slotted over the penalty. McCullen completed the scoring for the visitors, seven minutes from time, as he beat off Pichot to score.