Harlequins may have to wait to find out if they have qualified for the Heineken Cup quarter-finals, even if they defeat Connacht with a bonus point at the Sportsground in Galway on Friday night.

If Toulouse win at Gloucester, Quins will finish second in the pool and their fate will hinge on the outcome of Clermont Auvergne's tussle with Ulster on Saturday and the matches involving Edinburgh and Cardiff Blues the following afternoon.

A bonus-point victory would take Quins to 21 points, a tally the Blues and Edinburgh, who are tied on 17 points at the top of Pool Two, would reach with simple victories in their clashes against Racing Métro and London Irish respectively, while two bonus points for Ulster in defeat at Clermont would take them to 21, a total the French club would reach with a bonus-point win.

It would then come down to who had scored the most tries in their group matches. Quins have 10, three fewer than Edinburgh, who in turn are three behind Ulster. The Blues have mustered a mere six.

It would be Quins' first appearance in the last eight since the Bloodgate quarter-final against Leinster in 2009. The referee in Galway will be Nigel Owens, who was in charge at the Stoop when the then director of rugby at Harlequins, Dean Richards, engineered a fake blood substitution to bring a kicker on to the field in the closing minutes with his side a point down. "This is a big game for us," said the Quins centre Matt Hopper, who has made a big impact since joining from Cornish Pirates last summer. "The good thing about the way we are playing at the moment is that everyone is very confident with what we are trying to do."

Connacht gave Quins a fright in the opening round and Hooper said: "They are not doing too well at the moment but they showed at the Stoop what they can do. They are a dangerous team and we know that."