Munster tried gamely to get back in contention but Northampton sealed the win when Hendy scored his second try seven minutes from time.
Munster’s hopes of advancing to the quarter-finals of the Investec Champions Cup for the 20th time ended when they went down away to Northampton Saints on Sunday afternoon.
It was a highly entertaining encounter between the two rivals which swung one way and then the other before Northampton Saints sealed their place in the last eight, leaving Graham Rowntree’s side with just their defence of the BKT United Rugby Championship crown to play for this season.
Early Munster pressure went unrewarded as Northampton Saints defended well and kept their line intact.
The home side then countered and hit the front after ten minutes when full-back James Ramm got over and Fin Smith converted.
Munster replied five minutes later and scored off a good lineout move with Seán O’Brien getting through the cover to score. Jack Crowley converted to make it 7-7.
Munster pushed on from there and again scored from a lineout after going to the right corner with a penalty. They worked the ball across the field and with a penalty advantage, full-back Mike Haley cut through to score, with Crowley’s conversion pushing Munster 14-7 in front.
However, Northampton levelled before the break when winger Tommy Freeman scored and Smith converted to make 14-14 at the break.
Both sides had chances to edge in front after the break but it remained scoreless for the third quarter before Northampton Saints hit the front after 61 minutes when replacement winger George Hendy scored an unconverted try in the right corner.
Munster tried gamely to get back in contention but Northampton sealed the win when Hendy scored his second try seven minutes from time.