Tries from Zane Kirchner, Adam Byrne and Rory O'Loughlin helped the visitors into a 20-19 lead by the interval, while they pulled clear in the second half thanks to Rhys Ruddock and replacement Barry Daly crossing the whitewash.

Ross Byrne added three conversions and two penalties for Leinster, who were clinical on turnover ball with openside Josh van der Flier impressing as man-of-the-match.

Craig Ronaldson booted four first-half penalties and added the conversion to Danie Poolman's try as Connacht battled hard in the opening 40 minutes.

Dave Heffernan's 49th-minute try had Pat Lam's men ahead as they looked to crown their captain John Muldoon's 300th appearance with a derby victory, only to then concede 17 unanswered points.

Leo Cullen rested a number of his Leinster regulars and it was the hosts who led initially thanks to a Ronaldson penalty.

Frustratingly for Muldoon and his team-mates, they gave away two tries inside the opening 10 minutes.

Full-back Kirchner grabbed the first in the right corner after linking with Mike Ross and Adam Byrne, who claimed the second, gobbling up a loose Ronaldson pass to break clear from his own half.

A Denis Buckley-won penalty was turned into three points by Ronaldson for 12-6 and Connacht ended the first quarter with a typically swashbuckling try, the ever-threatening Tiernan O'Halloran causing trouble out wide for Leinster before Jack Carty's kick released winger Poolman to raid over from the opposite flank for a seven-pointer.

Ross Byrne and Ronaldson swapped penalties as the fast-paced but error-strewn fare continued.

Luke McGrath's sniping break saw him go close before Leinster used an overlap to send centre O'Loughlin over six minutes before the break.

Ronaldson responded off the tee to leave just a point between the sides. Injuries robbed the game of wingers Niyi Adeolokun and Dave Kearney, but O'Halloran was a one-man box of tricks for Connacht.

Time and again, the Clifden man injected the necessary pace into Connacht attacks, one such surge seeing him link with Kieran Marmion and although McGrath denied his opposite number, the ball was transferred to the left where hooker Heffernan was able to finish off.

Unfortunately for the eager home support, that proved to be Connacht's final score.

Leinster upped the ante, seizing on another loose pass as Van der Flier pressed in the 22 before his back row colleague Ruddock rumbled over from close range to pocket the bonus point.

Ross Byrne's conversion made it 27-24 to Cullen's side and Connacht redoubled their efforts, O'Halloran leading their charge before a Carty pass was plucked down by a leaping Adam Byrne to foil a promising move.

Connacht's adventurous play, this time near halfway, resulted in a fifth Leinster try, prop Buckley's pass going to ground after he was tackled and replacement winger Daly hacked through and collected the bouncing ball to dot down.

Number 10 Ross Byrne completed the scoring with a conversion and a subsequent penalty.