Leinster put their Champions Cup exit behind them to come from 16-0 down to notch their first win in the Rainbow Cup at the Sportsground.
And Hugo Keenan brushed off his Lions disappointment to run in a hat-trick in an eight-tries-to-two win.
Ten changes to the side that went down to La Rochelle last Sunday led to a poor start but once Leinster got moving, Connacht just had no answer to the power and pace of Leo Cullen’s men.
Connacht raced into a 16-0 lead after just 13 minutes as they punished a sleepy Leinster opening with some fired-up rugby that cracked holes in the cover.
Two early penalties from Conor Fitzgerald gave Connacht a perfect platform and they got a huge boost when scrum-half Caolin Blade, who scored two tries in the win away to Ulster last time out, intercepted from deep after prop Finlay Bealham’s hit was enough to disrupt Luke McGrath’s delivery.
Fitzgerald converted from in front of the posts and then added a penalty from the same area to leave Leinster with an uphill task but they met the challenge head-on and blasted home for five tries before the break to lead 33-16 at the interval.
Hugo Keenan may have been disappointed not to get a call from Warren Gatland in midweek but he showed exactly how devastating he can be as he raced through for two tries in five minutes before completing his hat-trick in the closing stages.
Hooker James Tracy barged over to put Leinster in the lead for the first time after 22 minutes and further tries from Ross Molony and former Connacht player Cian Kelleher put them in a commanding position at the end of an opening half where both sides were unsuccessful in their captain’s challenge trying to overturn tries.
Andrew Porter crowned his Lions inclusion by getting Leinster’s sixth try after Connacht again failed to defend a lineout maul, with Byrne converting to make it 40-16.
And after Connacht hooker Dave Heffernan was held up over the line, Leinster countered and scored off another penalty to the left corner with Scott Fardy finishing another good driving maul.
Leinster were denied an eighth try when Sean O’Brien did superbly to force Dave Kearney to knock-on as he grounded the ball after a break from inside their own 22, and Connacht came downfield and after sustained pressure pulled back a try when Peter Sullivan scored after a long pass wide from Fitzgerald.
Leinster hit the half-century when Keenan scored in the right corner just over a minute from the end.
tries, C Blade, P Sullivan; con, C Fitzgerald; pens, C Fitzgerald 3.
tries, H Keenan 3, J Tracy, R Molony, C Kelleher, A Porter, S Fardy; cons, R Byrne 5.
J Porch; P Sullivan, S O’Brien, T Daly, M Healy; C Fitzgerald, C Blade; D Buckley, D Heffernan, F Bealham; N Murray, G Thornbury; E Masterson, C Oliver, J Butler (c).
A Papali’i for Butler 30, HIA; O McNulty for Healy 30; C Prendergast for Oliver 55; S Arnold for Porch 55; D Robertson-McCoy for Bealhan 57; M Burke for Buckley 57; J Murphy for Heffernan 65; K Marmion for Blade 65.
H Keenan; C Kelleher, G Ringrose, C Frawley, D Kearney; R Byrne, L McGrath (c); P Dooley, J Tracy, A Porter; R Molony, S Fardy; J Murphy, S Penny, J Conan.
J van der Flier for Conan 25, HIA; R O’Loughlin for Frawley 37; T Furlong for Porter 55; D Sheehan for Tracy 55; E Byrne for Dooley 55; J Larmour for R Byrne 55; R Baird for Murphy 63; R Osborne for McGrath 63.
Frank Murphy (IRFU).