Saracens start title defence at Northampton
Saracens will hope to become the second club in history to seal a European three-in-a-row when they kick-off their title defence at Northampton.
The all-Premiership clash on Sunday, October 15, is only one of a series of mouth-watering confrontations in the fixtures schedules for Rounds 1 to 4 of the Champions Cup and Challenge Cup which have been announced by tournament organisers EPCR.
Scarlets, last season's PRO12 winners, will travel with confidence to Stade Félix Mayol to take on the might of Toulon in a Sunday, October 15 fixture which will feature Leigh Halfpenny's return to his old stamping ground.
Premiership champions, Exeter Chiefs, host Glasgow Warriors at Sandy Park on Saturday, October 14 in Pool 3, while last season's tournament runners-up and Top 14 winners, Clermont, continue their search for ultimate European glory against the Ospreys at the Liberty Stadium on Sunday, October 15.
Ulster will be determined to improve on their 2016/17 pool stage performance when they go head-to-head with Wasps at the Kingspan Stadium in the opening Champions Cup tie of the season on Friday, October 13, and Harlequins are up against tournament first-timers La Rochelle at the Twickenham Stoop the following day.
Highlights of the crucial back-to-back clashes include a repeat of last season's final between Saracens and Clermont, while Leinster against Exeter is certain to pack them in to Dublin's Aviva Stadium in Round 4 on Saturday, December 16.
In addition, the December meetings of European warhorses, Leicester Tigers and Munster, as well as the match-ups between two more former tournament winners, Bath and Toulon, are guaranteed to heat up the pre-Christmas chill.
Holders Stade Français will open their Challenge Cup defence with an away trip to tournament newcomers Krasny Yar of Russia on Saturday, October 14, and Switzerland will stage a Round 1 match when Oyonnax meet Connacht at the Stade de Genève on the same day.
The European season kicks off with the clash of last season's defeated finalists, Gloucester, and Pau at Stade du Hameau on Thursday, October 12.
The dates, kick-off times for the Round 5 and 6 fixtures in both tournaments will be announced in December following the completion of the Round 4 matches.