Glasgow Warriors six-try win over Benetton Treviso was their sixth in a row and has moved them into the top four.
After a slow start to the season, the Warriors seem to be coming good at just the right time for the semi-finals.
Stuart Hogg continued his good form with a man of the match performance and the Scots will be optimistic of finishing strongly with two of their remaining four regular season games against Zebre.
2. Connacht's squad is put to the test:
Injury-hit Connacht were unable to recover after slipping to 18-3 down against Ulster but showed their strength in depth with performances from academy product Peter Robb and debutant Shane O'Leary.
The 18-10 defeat means Connacht still haven't won in Belfast since 1960 and have been knocked off the top of the Guinness PRO12 on points difference.
Games against play-off chasing Munster and Glasgow in the coming weeks will further test the quality across the Irish squad.
3. Play-off race will go down to the wire:
Just ten points separate third and eight in the Guinness PRO12 table after Cardiff Blues 28-22 win over Scarlets at the Parc Y Scarlets.
There are just three games to go and the Blues can't afford any slip-ups but they've kept themselves in with a chance with a vital four points.
The return of Wales captain Sam Warburton, who put in a man of the match performance at the weekend, could prove decisive.
4. Sexton wins battle of No. 10s:
Jonathon Sexton scored all sixteen points to help Leinster to victory over Munster at the Aviva Stadium on Saturday, a result which sees them replace Connacht at the top of the Guinness PRO12 table.
Munster's Johnny Holland had scored all 13 of his side's points but was replaced by Ian Keatley just before the hour mark.
Keatley, who has four Irish caps, missed a penalty to put his side in the lead at 13-13, something Sexton did not and it finished 16-13.
5. Zebre need their home comforts:
Zebre will be delighted to return to the Stadio Sergio Lanfranchi on Friday night after failing to score in each of last three games - all away from home.
Despite their struggles they remain three points ahead of Italian rivals Benetton Treviso in the race for the Italian spot in the European Champions Cup.
Can a return to Italian soil mark a return to form for Gianluca Guidi's men?
6. Underhill lets his rugby do the talking:
With much talk of 19-year-old Sam Underhill's future in the past week, the young flanker did his talking on the pitch with a try and man of the match performance.
Underhill helped Ospreys to a 20-26 win over Newport Gwent Dragons which will only promote further talk about whether he'll earn an England call this summer.
Reports suggest Eddie Jones wants to invoke the RFU's "exceptional circumstances" clause for the flanker who is currently studying at Cardiff University.
7. Another nail-biter in classic rivalry:
Comfortably the highest attendance of the season to date, the 43,108 fans who packed into the Aviva Stadium on Saturday fully justified Leinster's decision to move the game from the RDS Arena.
And while the 16-13 victory saw just a single try a piece, there was no lack of drama and tension in a gripping game which went right down to the wire.
A last minute gamble from Dave Kilcoyne as he took a quick tap instead of an almost certain three points failed to pay off for Munster.
8. Competition for Welsh ten jersey:
Gareth Anscombe scored 18 points for Cardiff as he holds onto the kicking duties for the Blues despite Rhys Patchell leading the Guinness PRO12 points scoring charts with 174 points.
Patchell, who started at full back on Saturday, moves to Scarlets next year to find regular first XV action in the no. 10 jersey leaving Warren Gatland with plenty of options behind Welsh international Dan Biggar.
9. European week gives players a rare week off:
With the race for the European places incredibly tight, how will this weekend's European weekend affect the players' preparations?
In the Challenge Cup semi-finals, Connacht will look to bounce back from their defeat to Ulster when they travel to Grenoble while the Dragons take on Gloucester at Kingsholm.
Meanwhile Glasgow Warriors could go third as they play their game in hand against Zebre while the other teams have their feet up.
10. Fears for Wales next season:
As things stand, Scarlets would be the Wales only representatives in next season's European Champions Cup with all four Irish clubs in the top six.
Ospreys look very likely to miss out while Cardiff Blues need a flawless end to the season if they're to force their way into the qualification places.
The Dragons could sneak in the back door should they win the Challenge Cup.
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