Munster moved top of Pro14's Conference A after capitalising on Glasgow Warriors' defeat to in-form Benetton Treviso.
Bath finished the game with 11 men as they suffered defeat to lowly Worcester Warriors in the 98th minute.
Saracens welcomed Billy Vunipola back for Friday's trip to Sale Sharks but he could not inspire them to Premiership victory.
Toulouse ended 2018 on a high note, dishing out a crushing defeat to Toulon in one of three Top 14 games on Sunday.
Jason Tovey's late penalty gave the Dragons a first win over the Ospreys since Boxing Day 2014.
Bristol Bears ended 2018 with a huge win over Newcastle Falcons, while Bath moved up to fifth with victory over Leicester Tigers.
The battle between top and bottom in the Top 14 table stayed true to form, Clermont running out comfortable winners on the road.
Munster ended a four-game losing streak against Leinster with a 26-17 triumph on Saturday, while Edinburgh retained the 1872 Cup.
Calum Clark and David Strettle scored second-half tries as Saracens rallied to beat Worcester Warriors, while Harlequins held off Wasps.
Having suffered their first Premiership defeat of the season in their last away game, the Exeter Chiefs lost again at Northampton Saints.
For the second time in the Pro14 season, Ulster were beaten by Irish rivals Connacht.
The top two in the Top 14 table could not be separated as Clermont Auvergne and Toulouse shared a thrilling draw.
Bath are into the Premiership's top six after beating Wasps, while Gloucester won at Newcastle Falcons.
A victory over Zebre saw Benetton close to within three points of third-placed Scarlets in Pro14 Conference B.
Connacht scored four tries but still lost out to Leinster, who rallied from 17 points down to triumph in dramatic circumstances.
Stade Francais moved up to fifth in the table as Toulon and Racing 92 ran out convincing winners in Saturday's Top 14 action.