Leinster left clinging to bonus after suffering dose of set-piece misery against Harlequins
Harlequins 24-18 Leinster
Leinster have been down this road before and know that the journey is manageable, if not ideal.
Defeat at the Stoop was not part of their plan to return to the top of the European tree, nor was another toothless attacking performance but the losing bonus point is some solace as they face into a quick turnaround before doing it all again at the Aviva.
They will need to be a lot better next week after enduring a torrid time at the scrum, while too often they were far too lateral with ball in hand despite an improved display from Jimmy Gopperth.
Once more at this venue, it came down to a drop at goal but there would be no return for Nick Evans, who limped off after 13 minutes and this time Danny Care closed out the game with an impressive strike.
Harlequins top the pool at the halfway stage, but given they finished the match with the ball in Leinster territory, they might regret kicking it dead rather than ramming home their advantage.
That was secured in a hectic five-minute period before the hour mark as Nick Easter powered over and Alesi Tikoirotuma ran an intercept home.
According to their coach, Leinster "should have been good enough to win from there" and they narrowed the gap to three through Ian Madigan, but they couldn't close it out.
"I thought we came back into it very well," Matt O'Connor reflected. "They can get away from you pretty quick. The point is important. There's no question."
The Australian lamented his side's lack of control with ball in hand, particularly during a first half where they made a habit of squandering field position when they began to look threatening.
Ultimately, though, their set-piece cost them. As a result, they spent far too little time in the Quins' 22 and never looked like scoring a try.
Leinster were sloppy in a disjointed first half even though Madigan put them in front after just three minutes.
Nick Evans levelled soon after when Jack McGrath went off his feet at a ruck and Tim Swiel put Harlequins in front.
Leinster's defence held when called on and they managed a rare trip into enemy territory as Sean Cronin's throw to the tail gave Gopperth the platform to break the line and off-load to Luke Fitzgerald, but the hosts killed the ball and Madigan levelled.
McGrath then went off his feet and Swiel kicked the penalty, but Madigan was able to level before the break and another Quins collapse allowed him nudge the Blues in front after half time.
Despite a fine Rhys Ruddock burst, it was the English side who looked more threatening and Marler turned down a kickable penalty to go for the corner to ram home their edge.
Although Leinster disrupted the throw, the Quins pack retained the ball and while the maul didn't get them there, they used their carriers to batter the Leinster line until former England No 8 Easter forced his way through McGrath's tackle to score.
Swiel converted and Leinster began to open up and things looked promising when Kearney's perfectly weighted chip allowed Fanning to storm into the opposing 22.
Leinster went wide, but Fijian Tikoirotuma read Kearney's intentions brilliantly and picked off his pass to Zane Kirchner, running the length of the field to score.
Despite Swiel shanking the kickable conversion, Quins held a two-score lead.
Some poor discipline from the hosts allowed Gopperth to establish field position and with Isaac Boss dictating the tempo, Dave Ward conceded a penalty that allowed Madigan to narrow the gap to six points.
Soon after, he nailed a penalty to make it a three-point game. But things turned again as Quins attacked and Care nailed his drop-goal on the run.
They could have gone for the jugular, but were content with taking a three-point lead at the helm of Pool 2.
All to play for next week at the Aviva stadium then, with ticket sales heading upwards of the 35,000 mark.