Van der Flier leads charge as rampant Leinster blow Ospreys out of the water
Leinster 31 Ospreys 19
If Leinster can sort out these second-half slumps, they'll be a force to be reckoned with again.
With Johnny Sexton back on board, Cian Healy beginning to look like his old self and Josh van der Flier responding to Dan Leavy's brace last weekend with a double of his own, there are reasons for optimism among the 13,357 who defied the bus strike and made their way to the RDS.
At close to full strength, Leo Cullen's men produced an aggressive performance of real quality to brush aside the early Pro12 pace-setters, who struggled with the step up in intensity and class after easy wins over Zebre, Connacht and Treviso.
Although Sexton looked sharp on his first outing of the season, the home side's attack wasn't as fluid as they'd like. Yet there was a lot to admire about their approach as Jamie Heaslip carried hard and Isa Nacewa put in some bone-shuddering tackles.
Sexton marked his return from shoulder surgery with a try and a second-half yellow card, which allowed the visitors to get within a try of leaving with two bonus points, far more than they deserved.
The Ospreys came into the game having secured maximum points from their opening three games, but they never got going and had conceded four tries by the 46th minute.
Leinster got plenty of early reward from kicking to the top right -hand corner of the pitch, where they repeatedly asked stand-in full-back Sam Davies and winger Ben John questions.
Sexton opened the scoring with a penalty after one such foray and, although their attack was somewhat sluggish, Leinster's defence was aggressive and a big Dave Kearney shot on James King forced the Ospreys back on to the back foot.
The Welsh side relied on their breakdown to stay with Leinster, who spent 70pc of the first half in possession and 74pc in opposition territory.
Those sort of figures will eventually tell and after 20 minutes the hosts got in for their first try as the impressive Noel Reid kicked to the sweet spot and Nacewa forced Davies into touch.
Although the lineout maul couldn't get over the line, Sean Cronin led the second wave and four more forwards battered the Ospreys line before Healy popped the ball to van der Flier, who did well to touch down.
Sexton converted and Leinster's defensive aggression continued. A knock-on from the out-half invited a rare Ospeys foray forward. They worked a good move up the right wing where Josh Matavesi found Dan Biggar who, in turn, fed Jeff Hassler.
The winger only had to shift the ball on to Davies, but a moment's hesitation invited an almighty hit from Nacewa which ended his march.
The Ospreys' night got worse when Dmitri Arhip was sin-binned for clothes-lining Nacewa, and Leinster were ruthless in his absence.
With the Moldovan tighthead off, Luke McGrath was denied a try by the television match official who deemed Sexton's clever attempt to keep the ball alive to have gone forward. That didn't bother the Leinster pack, who forced a penalty from the scrum and then won a penalty try through their utter dominance.
Sexton converted, and he wasn't finished there and got on the scoreboard with a neat finish on the stroke of half-time after more good work from Healy.
The bonus point was secured within six minutes of the restart as Van der Flier raced on to a flat Sexton pass and shrugged off Arhip's attempted tackle to score.
The Ospreys finally got on the board when Ashley Beck spotted a huge overlap and John sauntered over.
After Edinburgh came back from a losing position last week to make a game of it, Cullen won't be happy that Sexton's yellow card for multiple team infringements was followed by tries from Dafydd Howells and James King.
But, when the coach ponders the performance over his coffee this morning he has plenty of positives to draw on after a largely impressive night's work.
Leinster - Z Kirchner; I Nacewa (capt), G Ringrose, N Reid, D Kearney; J Sexton (J Carbery 80), L McGrath (J Gibson-Park 61); C Healy (J McGrath 50), S Cronin (J Tracy 55), T Furlong (M Ross 65); D Toner, M Kearney (R Molony 55); J Murphy (R Ruddock 50), J van der Flier (D Leavy 72), J Heaslip.
Ospreys - S Davies; J Hassler (D Howells 61), A Beck (D Evans 65), J Matavesi, B John; D Biggar, R Webb (T Habberfield 61); P James (N Smith 47), S Baldwin (S Parry 47), D Arhip (M Fia 65); L Ashley, AW Jones (capt); J King (M Fia 30-ht), J Tipuric, T Ardron (D Baker 48).
Ref - M Mitrea (Italy)