Tommy Seymour scored four tries in an outstanding individual display as clinical Glasgow Warriors beat Leinster 33-25, before Ospreys overcame Connacht to go top of the Pro12 table.
Seymour grabbed a brace in the 41-5 rout of champions Connacht in the first game of the season last weekend and the Scotland wing was the star of the show in another impressive performance from Glasgow on the new synthetic pitch at Scotstoun Stadium.
Leinster defeated Benetton Treviso in their first game of the season and were on course to follow that up with a victory over Gregor Townsend's men when they led 22-12 early in the second half.
A converted Rob Kearney try put Leinster in front after Seymour had gone over in the corner 15 minutes in, then Josh van der Flier and Zane Kirchner dotted down late in the first half following a score from Tim Swinson.
Seymour came to the fore following the interval, plucking a stray pass from Joey Carbery to score his second try and making the most of another error to complete his hat-trick.
Another try from the former Ulster flyer seven minutes from time made sure, with Henry Pyrgos scoring eight points with the boot for the Warriors.
Rhys Webb scored a try in each half as Ospreys consigned Connacht to back-to-back defeats with a 32-11 victory.
Tyler Ardron and Jeff Hassler also touched down in the final 10 minutes to give Ospreys the bonus point and move them above the Warriors.
Departing Ulster scrum-half Ruan Pienaar followed up his man-of-the-match display in the victory over Newport Gwent Dragons by scoring a try and seven points from the tee in a 22-11 win at Treviso.