Wales scrum-half Rhys Webb bagged a brace of tries as Ospreys beat Ulster 31-20 to go top of the Guinness Pro12 table on Saturday.
Dan Biggar and Hanno Dirksen also crossed the whitewash in the bonus-point win at Liberty Stadium, while the former adding 11 points with the boot.
Late scores from Rob Herring and Tommy Bowe salvaged some pride for the Irish province, but the damage was already done.
Glasgow are in second after coming from behind to edge out fellow high-flyers Munster 21-18 at Scotstoun Stadium.
The visitors led 18-9 at the break thanks to tries from JJ Hanrahan and Robin Copeland, but Leone Nakarawa touched down as Glasgow rallied and Jonny Gray's 73rd-minute try completed the fightback.
Edinburgh were the big winners on Friday as they crushed basement dwellers Treviso 48-0 at Murrayfield with six unanswered tries.
Sam Hidalgo-Clyne set the tone with a first-minute score, while substitute Willem Nel enjoyed a double strike and Mike Coman, Grayson Hart and David Denton also went over.
Josh Navidi again impressed with a couple of tries as Cardiff beat Scarlets 21-9 and Zane Kirchner wrapped up Leinster's 21-11 defeat of Connacht with a late score.
Newport Gwent Dragons climbed above Zebre in the table thanks to a 25-11 victory over the Italian outfit in Wales on Sunday.
Centre Ross Wardle, winger Hallam Amos and lock Rynard Landman scored tries as the Dragons took advantage of Mauro Bergamasco and Leonardo Sarto being sent to the sin bin.
However, their second win of the season was marred by an injury to Wales No 8 Taulupe Faletau.