Scarlets number eight Rory Pitman scored the only try as Scarlets edged a tight 19-9 victory over Glasgow Warriors.
Table-topping Ospreys aim to continue their perfect start to the Guinness PRO12 season when they travel to Ulster.
Glasgow Warriors have completed the signing of utility back Fraser Lyle on a deal that runs until the end of the season.
Check out video highlights from round seven of the Guinness Pro12, which featured wins for Ospreys, Ulster and Leinster.
Nikola Matawalu scored the only try of the match as in-form Glasgow claimed a hard-fought 17-9 victory over Treviso.
Table-toppers Ospreys host Connacht on Friday looking to make it seven wins on the bounce in the Guinness PRO12.
Finn Russell kicked all Glasgow's points as the Warriors battled their way to a 15-13 victory at Montpellier.
Toulon's European Cup victory over Ulster proves they're the team to beat once again, says Stuart Barnes.
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