A late penalty by Ian Madigan earned Leinster a narrow 14-13 win at home to Harlequins in the European Champions Cup.
In a tight contest, it took until after the 20th minute for either team to get on the scoreboard as Madigan scored the first of his three penalties.
Leinster's Jamie Heaslip then expertly picked the ball up from the scrum and offloaded to full-back Isaac Boss, who crossed for the only try of the first half.
Harlequins failed to get off the mark in the opening period and England's Mike Brown had a try ruled out for a knock-on early in the second half.
Brown did score a legitimate try soon after and a couple of penalties from kicker Tim Swiel saw them take the lead with just over ten minutes to go.
However, Leinster came back and forced another penalty, and Madigan sent the ball through the posts to send the Irish side joint top of Pool 2.