Gloucester ran in six tries against London Welsh at Kingsholm, with number eight Ben Morgan grabbing a hat-trick in a 46-20 win.
A strong Gloucester side were comfortable winners thanks to tries from Shane Monahan, Akapusi Qera and Koree Britton along with Morgan's hat-trick, with Freddie Burns kicking four penalties and two conversions.
"I'm delighted for Ben Morgan," said Gloucester assistant coach Carl Hogg.
"He and the others showed great professionalism to come back from their international environment to play a club game today."
Exeter triumphed at home against a youthful Ospreys side in a 23-13 win, with Will Carrick-Smith and Myles Dorrian both scoring tries for the hosts and Henry Slade adding 13 points with the boot.
Number eight Morgan Allan picked up a try for the visitors with young fly-half Sam Davies adding two penalties.
The Scarlets saw off fellow Welsh side Cardiff Blues in a 22-16 win thanks to penalty kicks from Liam Williams, Gareth Owen and Aled Thomas (3), adding to a Penalty Try in the first half.
Flanker Luke Hamilton grabbed a try for Cardiff but was also sin-binned late into the match, Cardiff's others points coming from three penalties and a conversion from fly-half Gareth Davies.
Exeter 23-13 Ospreys
Gloucester 46-20 London Welsh
Scarlets 22-16 Cardiff Blues