The January contests promise to be absolute crackers after the Ospreys produced the shock of the round when they inflicted the first defeat of the campaign on the four-times champions Toulouse to throw qualification wide open.
Wing Eli Walker scored the game's only try in the Ospreys 17-6 victory over the French giants at the Liberty Stadium which keeps the Welsh side's slim chances of a place in the knock-out stages alive.
This was the Welsh side's first victory over the most successful side in Europe but they know they still have to beat the Leicester Tigers and Treviso to stand any chance of a quarter-finals place.
The Ospreys win means there are only five points between them, leaders Leicester Tigers on 14, Toulouse stuck on 13 and the Welsh club on nine with two fascinating rounds of the Pool stages still to play in the New Year.
The PRO12 champions may be third in the Pool and have their own ambitions of a quarter-final place but they look like the side who could dictate qualification for the last eight.
The Tigers were given an almighty scare by an impressive Treviso side in Italy but managed a narrow 14-13 last-gasp win thanks to a penalty try awarded in the 77th minute following a succession of collapsed scrums.
The two-times winners saved their blushes to keep themselves in the hunt for a Heineken Cup quarter-final place but they have an away trip to play the Ospreys and a home clash with Toulouse in the last two rounds.
Treviso, who have yet to record a win in this Pool, will be rueing the indiscipline which cost them against the Tigers but they have started to establish a burgeoning reputation on Italian soil.
