A Jack Carty penalty and a Tiernan O’Halloran try accounted for the home teams scores, but – after Tom Daly’s red card after just two minutes – playing with a man down for the majority of the game, Leinster ran out winners.
The home team will face Bennetton away in the United Rugby Championship next weekend.
The contest began with a typical Interprovincial intensity and Leinster were reduced to 14 men temporarily when Tommy O’Brien was reprimanded for a tackle in the air on Niall Murray right from the game's kick-off.
However, Connacht soon joined the away team in losing a man when Tom Daly was red-carded for a tackle on Ciaran Frawley, meaning both sides were brandished cards in the opening two minutes.
The away side were soon restored to their full complement and they began to put pressure on Connacht, whose defence was stout – withstanding phase after phase of close carries near their line – and Leinster eventually recycled the ball wide to Rory O’Loughlin to touch down. Ross Byrne added the conversion and Leinster found themselves 7-0 in front after an extremely physical opening fifteen minutes.
The hosts began to work their way back into the contest from that point, and after a huge break, including defence cutting carries from Niall Murray and Jarrad Butler, they earned a penalty that Carty slotted to put Connacht on the board and bring the score back to 3-7 midway through the first half.
With one score under their belts, the home team – whose scrum was proving a great launchpad, with replacement Matthew Burke and the entire front row to the fore – pushed for more, and their ambition bore fruit when O’Halloran caught an exquisite offload from Carty, who was playing from a penalty advantage, to touch down for the home teams opening try, which saw Connacht lead 8-7 going into the half time break.
The second half began with the same ferocious tempo with both teams committed to attack, but it was Leinster who opened the scoring for the second period when David Hawkshaw went over from close range. Byrne slotted the extras the away team lead 14-8.
Two tries soon became two for the visitors when Luke McGrath ran in a try from inside the 22. Hawkshaw added the conversion and the margin stretched to 21-8.
With their tails up, the away team secured their bonus point try when Ciaran Frawley dived on a bouncing ball in the in-goal area to take the score to 26-8 to Leinster. A fifth try soon followed when Tommy O’Brien fielded an offload to slide in for the five-pointer to take the score to 31-8.
Connacht were still game and dogged, but the man deficit told late on and Josh Murphy added Leinster’s sixth try – which Hawkshaw converted – to grow their lead to 38-8. O’Brien added his second score to take the final score to 45-8 in Leinster’s favour.
15: Tiernan O’Halloran
14: John Porch
13: Tom Farrell
12: Tom Daly
11: Oran McNulty
10: Jack Carty ©
9: Kieran Marmion
8: Jarrad Butler
7: Conor Oliver
6: Cian Prendergast
5: Niall Murray
4: Oisin Dowling
3: Jack Aungier
2: Dave Heffernan
1: Denis Buckley
16: Jonny Murphy for Dave Heffernan
17: Matthew Burke for Denis Buckley
18: Greg McGrath for Jack Aungier
19: Ultan Dillane for Niall Murray
20: Paul Boyle for Conor Oliver
21: Caolin Blade for Kieran Marmion
22: Sammy Arnold
23: Diarmuid Kilgallen for Oran McNulty