Leaders Leinster survived late pressure from Connacht to clinch a priceless win which takes them 10 points clear at the top of the Magners League.
Connacht had claimed an interval lead thanks to a try by Keith Matthews.
But Leinster, now playing with the wind, were ahead inside the first 10 minutes of the second half.
Felipe Contepomi landed a 35-metre penalty and replacement winger Shane Horgan beat off two tacklers to make the corner for the match-winning try.
In the closing moments and with Leinster's Cian Healy in the sin-bin, Connacht launched a stirring late fightback with their prop Ronan Loughney just inches short of the try line.
However, just moments later, Leinster claimed turnover ball and breathed a collective sigh of relief when time was called on their seventh successive league win.