Saturday’s results have turned Pool 2 into a three horse race after Ospreys 17-6 defeat of Toulouse and the Leicester Tigers’ inability to get a bonus point in Treviso.

The Tigers must go to Liberty Stadium, with Toulouse hosting the Italians, in January before hosting the French aristocrats in round six at Welford road in what looks set to be a winner-takes-all showdown.

Harlequins remained on course for a home quarter-final and topping Pool 3 with a 53-5 defeat of Zebre. Qualification can be secured by beating Connacht at the Stoop in round five, without having to worry about the trip to Biarritz in round six.

Castres’ nervy 10-8 victory over Glasgow leaves them second in Pool 4, three points behind Ulster, but the French must beat Northampton at Franklin’s Garden to have any chance of qualifying. Ulster can potentially win the group with a comprehensive win over Glasgow at Ravenhill in round five.

Exeter’s 30-20 defeat of the Scarlets gives them a slim mathematical chance of getting out of Pool 5 but they will need bonus point wins in Clermont and at home to Leinster. Still, they could put the final nail in Leinster’s coffin in round six.

Stretch clear

In Pool 6, Toulon destroyed the Sale Sharks yesterday 62-0 to stretch clear of Montpellier, who beat Cardiff Blues 34-21 on Saturday. Montpelier host Toulon in round six.

Finally, Racing Metro 92’s 15-6 win over Edinburgh at Murrayfield saw them lead Pool 1 for 48 hours but Saracens regained control with victory over Munster yesterday. Racing versus Saracens in round five could prove the definitive match of the group.

“When you have a large amount of your squad playing international rugby you don’t have a lot of time to prepare,” said Saracens captain Steve Borthwick. “They were away for five weeks but this week, despite a six-day turnaround, we had a little bit more time to prepare.”