Elsewhere, Munster and Ulster slumped to defeat
Connacht and Zebre produced a ten try thriller at Stadio Sergio Lanfranchi in Italy on Saturday evening, with the result putting the Western province top of the Pro12 table.
Matt Healy bagged himself a hat-trick while Niyi Adeolokun dived over for a brace with Kieran Marmion adding the other.
In one of the games of the season, open, exciting running rugby was the order of the day as both sides went for all out attack on the perfect surface in Parma.
Zebre have shown signs of progress all season and they showed it again on Saturday, refusing to wilt after Connacht opened up a lead a number of times.
Connacht will be disappointed with their defensive performance allowing Zebre to earn a try bonus point, but a bigger concern will be a nasty looking injury to Eoin Masterson.
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Isa Nacewa's try was enough to give Leinster victory by the slenderest of margins in turgid conditions at Cardiff Arms Park on Saturday, giving them a second win on the bounce.
It was far from pretty for Leinster, who had Fergus McFadden sin binned for a dangerous tackle, but thanks to a late Eoin Reddan block down, they went home with the four points.
Scarlets deservedly edged out Ulster at the Kingspan Stadium on Sunday, with two tries from Michael Collins proving crucial.
Craig Gilroy and Luke Marshall scored two brilliant tries for the home side, but it wasn't enough as the boot of Aled Thomas gave the Scarlets a priceless win in the competition for a play-off position.
Munster fought back from a 14 point deficit before losing out by three points in a battle of two of the league's sleeping giants.
Dave Kilcoyne's two tries and Mike Sherry's effort weren't enough to overcome a resilient Warriors side in Kilmarnock.
Benetton Treviso 19-17 Newport Gwent Dragons
Ospreys 27-13 Edinburgh