The Ospreys picked up their first home win of the PRO12 season on Saturday night, beating Munster at the Liberty Stadium.
Full-back Richard Fussell and hooker Richard Hibbard crossed the line, and the home side were also awarded a penalty try. Fly-half Dan Biggar added 15 points with the boot.
The visitors were restricted to five penalties, as the Ospreys kept up their momentum after last week's win over the Scarlets.
The Scarlets themselves are heading in the opposite direction, losing their second game in succession after such a strong start to the season.
They raced into a 20-5 lead at Treviso, after two tries from winger Andy Fenby and 10 points from Rhys Priestland. The Italian hosts struck back with two tries, before fly-half Alberto Di Bernardo pinched victory with a long-range penalty in the dying seconds.