Saracens eased past Northampton Saints but table-topping Exeter Chiefs had to repel a second-half rally from Sale Sharks.
Saracens' defeat on Friday left the door ajar for Exeter Chiefs, who downed Newcastle Falcons to go top of the Premiership.
Leicester Tigers limped to defeat at Saracens, meaning the victors once again sit top of the Premiership.
Bath have announced that Taulupe Faletau will undergo further surgery on his right arm, which will make him unavailable for Wales.
Reported Northampton Saints target Jonathan Joseph is set to stay at Bath after signing an undisclosed contract extension.
Any hopes Toulouse had of snatching top spot in Pool 1 were extinguished as Leinster defeated Wasps to secure a home quarter-final.
Bath have confirmed number eight Taulupe Faletau broke his arm in his first match since recovering from the same injury.
Wales are set to have Taulupe Faletau available for the Six Nations, while Jonathan Joseph may be available for England.
All four Pro14 sides in European Rugby Champions Cup action on Saturday secured victories, three coming against French opposition.
Three weeks before the start of the Six Nations, Sam Underhill has been ruled out of the tournament in a significant blow to England.
Bath finished the game with 11 men as they suffered defeat to lowly Worcester Warriors in the 98th minute.
England's Sam Underhill will undergo a specialist review after suffering ankle ligament damage and could miss the start of the Six Nations.
Bristol Bears ended 2018 with a huge win over Newcastle Falcons, while Bath moved up to fifth with victory over Leicester Tigers.
Bath are into the Premiership's top six after beating Wasps, while Gloucester won at Newcastle Falcons.
Saracens battled past Cardiff Blues to stay top of Pool 3, while Toulouse came out on top in an entertaining clash with Wasps.
A low-scoring draw at Bath was enough to lift Sale Sharks back off the bottom of the table, although they were frustrated after leading.