It was a victory that gives Ulster 8 points but unless Cardiff cause a huge upset in Biarritz it means Ulster will not get through to the quarter finals.
Ulster played against the wind in the opening half and deservedly led 7-3 at the break thanks to a marvellous Neil McMillen try converted by David Humphreys. However Northampton struck back early in the second half when Ben Cohen showed some neat footwork to race in from 30 metres. Grayson added the conversion but shortly after Cohen was yellow-carded and Humphreys landed a drop-goal to tie the game. Grayson put the visitors back in front with 66th minute penalty.
In the final quarter Northampton were reduced to 13 when first Chris Budgen and then Mark Soden were yellow-carded, Soden for a high tackle on Humphreys and from the penalty Neil Doak levelled the game again.
Ulster continued to pound away at the Northampton line and were only denied by last gasp defence. However, in the end their persistence was properly rewarded when Humphreys landed a second drop-goal, three minutes into stoppage time, to give the home side a thoroughly deserved victory.