Munster and Ospreys captialised on Leinster's dropped points to boost their own Pro12 play-off hopes on Saturday.
Fifth-placed Leinster held Glasgow Warriors to a 34-34 draw on Friday, but their failure to complete a second-half fightback opened the door for their rivals to steal a march.
Munster were first to make their compatriots pay by picking up a 42-20 win over Connacht, pulling them level on points with second-placed Ulster and six clear of Leinster.
A low-scoring first half offered little hint of what was to come after the break, as Munster ran in five tries to Connacht's two in the second 40 minutes.
That quintet of touchdowns - all scored in the last 25 minutes - took Munster's tally to six for the match from six different scorers, bookended by Billy Holland and Keith Earls.
Having seen Munster cross the whitewash six times earlier in the day, Ospreys went one better by registering seven tries on their way to a 53-22 demolition of Zebre.
Dan Baker went over once in each half, while Ospreys' returning Wales contingent chipped in, Rhys Webb and Scott Baldwin scoring a try apiece amid Dan Biggar coming off the bench to kick a late conversion.
Ospreys had been one point adrift of Leinster, but now sit four clear of the Irish province in the final play-off position.
Gareth Davies is likely to face a ban after he was sent off for a headbutt shortly after coming on as a replacement during Scarlets' 26-15 defeat to Edinburgh.
The international scrum-half had been introduced shortly before the hour mark in a bid to swing the match in the hosts' favour, but his clash with Andries Strauss reduced Scarlets to 14 men as they failed to score a point in the second half.
In the day's remaining match, Newport Gwent Dragons won 32-17 at Benetton Treviso.