Northampton facing huge test against Ulster
Saints must avoid defeat at Ravenhill next Friday night to guarantee themselves a prized quarter-final place.
They are just one point away from reaching the last eight, edging tantalisingly close following their stirring 17-14 Franklin's Gardens victory over French champions Biarritz.
But Ulster's European record on home soil they have beaten French giants Toulouse and Stade Francais, among others, during previous Heineken Cup campaigns suggests Northampton face a severe test.
Ulster are also in quarter-final contention following their 33-21 Arms Park success against Cardiff, which was secured by a try double from flanker Neil McMillen.
"Their home record is awesome," admitted former England fly-half Grayson.
But Saints will have every chance if they can re-produce the battling qualities that saw them defeat Biarritz and consign their opponents to a probable early European exit.
Grayson had an off-day with the boot, missing all three of his penalty attempts. But half-back partner Matt Dawson successfully took over kicking duties, and substitute centre Peter Jorgensen's 77th-minute try secured an outstanding Pool Six win.
While Northampton stand on the verge of last-eight qualification, Heineken Cup holders Leicester booked their place by defeating Calvisano 40-22 in northern Italy.
The Tigers wrapped up Pool One, but their emphasis now is on trying to secure a home draw as one of the four best group winners.
In Munster's Pool 2, Gloucester remained in pole position thanks to a thumping 64-16 Kingsholm success against Italian whipping boys Viadana.
Gloucester posted 10 tries one of them by England wing James Simpson-Daniel on his return from glandular fever and there were doubles for Junior Paramore and Robert Todd.
French aces Toulouse continued preparing ominously for the knockout stages by humiliating Newport 70-18.
It was easily Newport's heaviest Heineken Cup defeat, and the 10-try romp must cast a shadow over the long-term futures of coaches Leigh Jones and Richard Hill.
The Black and Ambers are a pathetic, pale imitation of a side which beat Toulouse at Rodney Parade last season and lost by only 13 points when they travelled to south-west France.
Easy Pool Five winners Toulouse coasted home as Xavier Garbajosa (2), Yann Delaigue (2), Yannick Jauzion (2), Emile Ntamack, Jean Bouilhou, Vincert Clerc and Jean-Baptise Elissalde scored tries. Elissalde finished with 25 points.