Northampton booked a Zurich Championship semi-final trip to Bristol next month after an ill-tempered 38-14 victory over London Irish at the Madejski Stadium.

Saints wing Nick Beal's try double - and 18 points from fly-half Paul Grayson - steered Northampton into the last four.

Irish, who had already qualified for next season's Heineken Cup, fielded a second team.

But the game was still fiercely contested and littered with numerous off-the-ball spats.

Irish forwards James Cockle and Doug Wheatley were both yellow-carded, together with Saints' England hooker Steve Thompson.

The Exiles claimed that a combination of injuries, and three players - Justin Bishop, Barry Everitt and Richard Kirke - having reached English rugby's agreed 32-game season limit, underpinned their selections.

Brendan Venter (fractured cheekbone), Chris Sheasby (back) and skipper Ryan Strudwick (shoulder) were among those absent.

Irish paraded 15 changes from last month's victorious Powergen Cup final team when Northampton were crushed 38-7.

Saints, still to pin down a Heineken Cup spot before kick-off, included 10 internationals, although injuries sidelined England wing Ben Cohen and Australian centre Peter Jorgensen.

Irish though, made a blistering start, and went ahead after just 111 seconds when Saints full-back Joe Shaw and Beal hesitated fatally in defence and South African flanker Gavin Pfister powered over.

Fly-half James Brown converted, and although his opposite number Grayson slotted two quickfire penalties, Irish preserved their advantage despite seeing Cockle sin-binned for a technical offence.

But it couldn't last, and Beal sprinted through for a 20th-minute try - converted by Grayson - when Irish were temporarily reduced to 14 men.

There were plenty of fireworks - Saints scrum-half Matt Dawson and Irish flanker Paul Gustard twice brawling on the ground, while Northampton lock Jon Phillips remarkably escaped censure after throwing a punch at Kevin Burke.

Irish centre Simon Hunt was stretchered off, yet nothing could dampen Irish's resolve, and Worcester-bound wing Nnamdi Ezulike almost added a second try following a 40-metre break.

Irish knew they had to take their chances, and Northampton punished them on 35 minutes.

Dawson broke superbly from just inside Saints' half, and with the Irish defence totally disorganised, Beal cantered over for another touchdown that Grayson improved.

Prop Wheatley followed Cockle into the sin-bin following a high tackle on Dawson just before the break, and once again, Saints took advantage as skipper Budge Pountney claimed a try.

Grayson's touchline conversion gave Northampton a 25-7 interval lead, and left Irish facing a mountainous second-half task.

Another Grayson penalty put Saints further ahead - and Irish three converted tries behind - but the Exiles sensed a glimmer of hope when Thompson was yellow-carded on 54 minutes for a technical offence.

Irish battered away at the Northampton line, and an opportunist 59th-minute try by scrum-half Kevin Barrett, which Brown improved, lifted spirits.

But Northampton, somewhat predictably, pulled away again, finishing off with another Grayson penalty and a converted penalty try after centre John Leslie was bundled off the ball as he attempted to touch down