The Scarlets ran in six tries to mark Leigh Halfpenny's long-awaited return with a 43-21 thrashing of the Cheetahs in Pro14 on Sunday.
The Jaguares opened their 2019 account thanks to Rodrigo Bruni and Bautista Delguy in Buenos Aires on Saturday.
Zack Holmes scored 15 points as Toulouse extended their lead at the Top 14 summit, while Stade Francais boosted their play-off hopes.
Luca Sperandio and Niccolo Cannone scored two tries apiece as Benetton Treviso stretched their unbeaten run to eight games.
There was late drama for the Stormers against the Lions, while the Sharks were decidedly more comfortable against the Blues in Super Rugby.
Wales came from 10-3 down at half-time to claim a record 12th consecutive victory and go top of the Six Nations table.
Saracens' defeat on Friday left the door ajar for Exeter Chiefs, who downed Newcastle Falcons to go top of the Premiership.
Having been thrashed by England last time out, a much-changed France side produced a fine showing to down Scotland in Paris.
New Zealand pair Richie Mo'unga and Scott Barrett scored two tries each in a convincing win for the Crusaders.
Ben Morgan's brace led Gloucester to another big victory as they fended off a fast-finishing Saracens.
Glasgow Warriors closed the gap on Munster at the top of Conference A, despite both recording wins in the latest round of Pro14 fixtures.
The Reds threatened to upset the Highlanders in their Super Rugby opener, but Aaron Mauger's men made it two wins out of two.
Racing 92 ran out of time in their defeat to Toulouse, while La Rochelle survived a Top14 scare against lowly Grenoble.
Marnus Schoeman finished with a hat-trick in Buenos Aires on Saturday as the Lions started the 2019 campaign on a winning note.
In his first Super Rugby appearance, 29-year-old former sevens star Rosko Specman set the Bulls on the road to beating the Stormers 40-3.
Perpignan finally had a win to celebrate, while Clermont Auvergne were too good for Bordeaux-Begles in Top14.