Leinster 25-20 Wasps
Leinster came through a tough first examination in the Champions Cup as they edged out Wasps 25-20 at the RDS Arena.
Alapati Leiua's 23rd-minute try was added to by a cracking Christian Wade score as wind-backed Wasps built a 20-11 half-time lead, with Andy Goode kicking ten points with the boot.
Two penalties from Ian Madigan, coupled with a try from European debutant Darragh Fanning, kept Leinster in touch and they went up through the gears with third-quarter scores from Fanning and Dominic Ryan.
However, Wasps' scrambled defence earned them a deserved losing bonus point as they kept the Irish province at bay in the closing stages.
In their first European outing since Brian O'Driscoll's retirement, injury-hit Leinster were without ten players who lined out in last April's quarter-final against Toulon.
The hosts settled quickly, though, winning a scrum penalty and carrying forcefully in the 22 with Rhys Ruddock leading the charge. A close-in penalty was tapped over by Madigan.
But Wasps, who were without captain James Haskell due to illness, were not long in replying. Ashley Johnson used an overthrown Leinster lineout to cause concern in the home defence and Goode's 12th-minute penalty levelled matters.
Rampaging runs from Ruddock and Nathan Hughes lifted the tempo at the end of a tight first quarter, although a ruck offence by the former allowed Goode to make it 6-3.
It got even better for the visitors when Noel Reid's attempted pass to Fanning was juggled and gathered by Leiua - just outside the Wasps 22 - and the Samoan centre had the gas to run over unopposed.
Leinster replied just four minutes later as captain Jamie Heaslip bulldozed past Joe Launchbury in midfield and Jimmy Gopperth's inviting grubber kick was grounded by Fanning in the left corner.
Madigan's missed conversion left a five-point gap and despite failing to capitalise on breaks by replacement Rob Miller and Elliot Daly, Wasps added to their lead before the break.
It was a Christian Wade 'special' as the fleet-footed winger whizzed by Madigan on the outside, evaded Fanning's attempted tap tackle and dived over in the right corner past the despairing Zane Kirchner.
However, Goode's terrific touchline conversion was cancelled out by Madigan with the last kick of an entertaining first half.
Turning with the elements behind them, including a fresh rain shower, Leinster had to weather some early pressure before a Devin Toner block launched the blue shirts downfield.
Sean Cronin carried twice to good effect and Heaslip again made crucial yardage before Eoin Reddan released Fanning to go over on the right. Madigan's conversion made it a two-point game.
Goode pushed a right-sided penalty across the posts and Leinster were looking increasingly potent, with hooker Cronin careering through tackles and the hard-earned momentum led to flanker Ryan powering over from a few metres out.
TMO Derek Bevan confirmed the grounding and Madigan added the extras for 25-20, giving the hosts the impetus to push on in the final quarter.
Number 8 Hughes led Wasps' resistance at a scrum close to their own line and while Gordon D'Arcy and Kirchner had a couple of bites at the cherry, the bonus point try eluded Matt O'Connor's men whose opening win sees them join Harlequins at the top of Pool 2.