Leinster moved into second in the table with a five-try win over Zebre in Italy while Ulster took a firm grip on the top of the table.
There was better news at the other end of the table for the Dragons as well who ended a four-match losing streak as they edged out Munster, Tom Prydie doing the damage from the kicking tee.
TRY OF THE WEEKEND
Glasgow Warriors put a massive dent in Ospreys hopes of defending their RaboDirect PRO12 title and they had the predatory finishing of Sean Maitland to thank for the vital score.
The New Zealand born winger showed a great turn of pace to gallop after Nikola Matawalu's chip to the corner and even better hand-eye coordination to dab down before the dead-ball line.
BREAK OF THE WEEKEND
Leinster's bonus point win in Italy moved them into second in the table but they did not have it all their own way, going in at half-time with the scores tied at 17-17.
And Zebre had Sinoti Sinoti to thank for the try of the game, the Samoan coming off his wing to take an inside ball, bursting through the first tackler before sidestepping another to dive over for a fine score.
PLAY OF THE WEEKEND
Andrew Trimble might be the name on the scoresheet but Ulster's second try against Connacht was down to one man and one man only - Ruan Pienaar.
The South African danced clear down the right-hand touchline before his deft no-look pass out of the back of his hand released Trimble to race clear and stretch the lead against their Irish rivals.
PLAYER OF THE WEEKEND
The Scarlets took a massive step towards the semi-finals this weekend and it was Wales international centre Jonathan Davies who stole the headlines. The centre, who is a potential British and Irish Lion this summer, ran in a try in each half against the Blues and carried with real vigour throughout.
But the weekend belong to Tommy Bowe as the Ulsterman became the first man to notch 50 Celtic League tries in Friday's win over Connacht.
ONES TO WATCH
The return of Jonathan Sexton for Leinster has come at just the right time for the Irish region with the RaboDirect PRO12 play-offs and an Amlin Challenge Cup semi-final to come.
The fly-half notched 16 points against Zebre and gave Warren Gatland a timely reminder of his skills ahead of the Lions tour Down Under this summer.
Also serving notice of his Lions potential was Ryan Grant, the Scotland prop scoring two tries in his side's win against the Ospreys.
Tom Prydie was the star of the show for the Dragons as he grabbed a personal tally of 17 points as they returned to form with a win against an inexperienced Munster side.
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