Paris - Champions Cup holders Saracens will seek to make it 12 straight wins in Europe when they take on English Premiership rivals Sale on the weekend.On another weekend of mouth-watering line-ups, the issue of head knocks and concussion will also likely be raised after Northampton's Wales winger George North was stood down after a controversial incident in league action last weekend.
The Saints will take on Irish province Leinster in Friday's sole game without North, who was left looking to be unconscious when he lay prone with his head pressed into the turf after a tackle by Leicester's Adam Thompstone last weekend, but returned to the fray minutes after some treatment.
That left Northampton scrabbling to justify their medics' actions, before taking the decision to stand North down on Tuesday. The potential repercussions will be felt throughout Europe's leading clubs given the demands on players in an increasingly physical game.
In Pool 3, Sale captain Josh Beaumont was under no illusion of what to expect from Saracens, who beat them 28-13 in the Premiership last month.
"We've only just played them so we know what they're all about. But, they are champions of Europe so there's no bigger test," said Beaumont.
"The next two weeks gives us a chance to regain our form away from the Premiership. We just need to cut our silly errors out and then we can get some momentum going in to the next set of league fixtures."
Sale have drafted in rugby league converts Josh Charnley and Denny Solomona, the latter at the centre of a legal fight with previous Super League club Castleford Tigers.
Saracens, just two wins away from equalling Munster's record of 13 successive tournament victories set between 2005 and 2007, this week announced the signing of giant Australia lock Will Skelton to make up for Alistair Hargreaves' retirement.
The Mark McCall-coached Saracens, who slipped to a 13-11 defeat by Bath in the Premiership last time around, have not lost in Europe since they were beaten 13-9 by Clermont in the 2015 semi-final and last season became the first side to win all nine matches to take the title.
The other game in Pool 3 pitches Scarlets against Toulon.
Other great match-ups in Round 3 see Leicester, in Pool 1, put their two-game unbeaten record on the line at Thomond Park against Celtic League leaders Munster Rugby in a re-run of the 2002 final.
Top 14 leaders Clermont head to Belfast to face Ulster as they attempt to maintain their unbeaten record in Pool 5.
Toulouse will be seeking their first victory in Pool 2, away at Italians Zebre, and backs coach Jean-Baptiste Elissalde knows his side has no room for mistake, with unbeaten Connacht playing Wasps.
Toulouse went down 23-21 to the Irish team before a dramatic 20-20 draw with Wasps, "so we went from eight points to three," said Elissalde.
"As it's an open pool, we don't have the choice, we have to get the maximum points to be able to hope for qualification.