Well short of their best, Leinster did enough, as champions tend to do, with Ireland lock James Ryan (14 carries and 17 tackles) again impressive.
Todd Blackadder's Bath, with one victory from their past 11 matches and now unlikely to progress, were reduced to slotting a penalty in front of the sticks to collect a losing bonus point on the final play.
Toulouse continued their resurgence with a second away win, this time 24-16 over Lima Sopoaga's Wasps.
The four-time European champions are well back in contention after a barren run of six years without a title.
This victory over Wasps maintains their unbeaten run in Europe and surprise place ahead of Leinster atop their pool after three straight wins.
Sopoaga has admitted struggles to recapture his best form since moving north.
Among his challenges are defensive issues after Cheslin Kolbe bumped him off in a two-man attempted tackle on the way to a stunning solo try.
To be fair, Kolbe's sharp footwork and deceptive power have exposed many this season and, ultimately, led to a recall with the Boks.
Even with three pool games remaining, Wasps' hopes of progression appear shot and with Boks fullback Willie Le Roux and English internationals Nathan Hughes and Elliot Daly expected to leave the club at season's end, instability seems set to surround Sopoaga and Brad Shields.
It was a case of no Maro Itoje - the England lock out for four to eight weeks with a knee injury - no worries for Saracens who eventually looked ominous in putting eight tries past Gareth Anscombe's Cardiff Blues to also remain unblemished in Europe.
Anscombe had his moments returning to No 10 and helping Cardiff stay in touch at half time after the try of the weekend from fullback Matthew Morgan. Seek out his 75m effort if you get the chance. Another win for the small men.
Back from a two-month injury layoff, Mako Vunipola's presence at scrum time and his dominant carries took their toll on Cardiff. Turning into the wind, the visitors capitulated to be blown away 51-25.
In Paris, the on-field entertainment from Racing 92 matches their new state-of-art 32,000-seat indoor stadium, one complete with a near full width projector screen and 4G pitch conducive for open, running rugby.
With classy Scottish playmaker Finn Russell pulling the strings for the third unbeaten team, Racing are again a serious threat.
Their 36-26 win over Leicester Tigers was aided by the visitors copping two yellow cards, one to Manu Tuilagi who also finished a quality try on the outside loop.
But after falling three points short to Leinster in last year's final, Racing undoubtedly possess the attacking firepower to again test the best.
Don't expect Montpellier or Toulon to get close to those heights, though.
Their clash revealed why they will both battle to make it out of their pool.
Julian Savea, from the second-five role he has frequented this season, produced the touch of the match with a pick up off his toes, dart to the edge and fine long ball to put his winger away.
Otherwise, though, don't rush to watch the return match in Montpellier next week.
Toulon won 38-28 this match but managed to concede two tries in the final five minutes.
Their underwhelming pool - headed by Edinburgh - does, however, remain wide open.
Relentless Fijian No 8 Viliame "Bill" Mata, scouted from the sevens circuit, starred with 27 carries for 105m as Edinburgh scored 21 unanswered second half points to put away Newcastle 31-13.
Leading into the match Newcastle lost two tighthead props to injury in three days and had their request for dispensation over a replacement denied. Instead of opting for uncontested scrums, they started a loosehead and paid the price for the bizarre situation.
Completing the Scottish double act, Rennie's Glasgow picked up a bonus point in their 42-22 away victory in Lyon. With Lyon, rooted at the bottom of the pool with no points, at home next week, Glasgow should now push on and cement a quarterfinal position alongside Saracens.
Results have not been so positive of late for future Wales coach Wayne Pivac. A one point home loss to Ulster looks set to abruptly end Scarlets' challenge, despite last season reaching the European semifinals.
Ireland centre Will Addison, no doubt learning plenty from Jared Payne after his move into coaching, had some telling touches for Ulster to outshine Lions opposite Jonathan Davies.
After a dire first half at Limerick's Thomond Park, Conor Murray proved his class by providing the much-needed spark in his return match.
One snipe and offload to set up CJ Stander in particular caught the eye as Murray guided Munster to a largely uninspiring 30-5 win over limited Top 14 champions Castres.
That secured a sweep for Ireland's teams and propelled Munster to the top of their pool, three points clear of Johan Ackermann's increasingly resilient Gloucester who handed Exeter a 27-19 home defeat.
