Against a Leinster side, which was obviously stripped of a host of international star names away on international duty with Ireland in New Zealand, Webb inspired the Ospreys to an opening day RaboDirect Pro12 win.
Leading 27-3 at the break, the result never looked in doubt after three first half tries from the impressive Webb after just three minutes, winger Hanno Dirksen after 20 minutes and skipper Justin Tipuric on the stroke of half-time.
Dan Biggar also contributed 12 points with the boot in the first 40 minutes as a newlook Ospreys side, which has obviously lost the likes of Welsh internationals James Hook, Lee Byrne and Phillips, started the season in style.
Webb started and finished a flowing move early on, which involved impressive centre pairing of Andrew Bishop and Ashley Beck.
After being held up short of the line twice, Dirksen ensured it was third time lucky for the Ospreys as he showed tremendous strength to bury over in the corner after 20 minutes.
Biggar ensured the scoreboard continued to tick over with three conversions, a drop goal and a penalty in the first-half, with just a solitary three points from Mat Berquist for Leinster in a disappointing first period.
And Tipuric guaranteed the Ospreys finished the half in style as he chased down Webb's kick-through to score his side's third try.
It was a different story after the break, with Leinster playing low-risk rugby and dominating territory and the breakdown as they pressed the Ospreys line.
Within two minutes of the second-half, the Leinster pack saw the ball held up after a series of drives, while on 50 minutes Beck did brilliantly to wrap up flanker Kevin McLaughlin over the try line as he threatened to pull a score back for the visitors.
The Ospreys were further rocked on 52 minutes as skipper Tipuric was sin-binned for perennially infringing at the breakdown as Leinster threatened the unlikeliest of comebacks.
It was short-lived; however, as Leinster's Fionn Carr, signed from Connacht, was frustrated on 66 minutes as he was pulled back for a forward pass just as he seemed set to pull a score back for the visitors.
After a hugely entertaining first-half, a series of replacements after the break destabilized the Ospreys attacking intent, while needless errors from both sides saw the second 40 minutes scoreless.
The Ospreys will be disappointed not to get the bonus point after fluffing a series of attacking line-outs in the Leinster 22 after weathering an early second-half storm by the visitors.

| Ospreys Score Card | |||||
| Name | Tries | Conv | Pen | Drop | Pts |
|---|---|---|---|---|---|
| Rhys Webb | 1 | 5 | |||
| Justin Tipuric | 1 | 5 | |||
| Dan Biggar | 3 | 1 | 1 | 12 | |
| Hanno Dirksen | 1 | 5 | |||
| Total | 3 | 3 | 1 | 1 | 27 |
| Leinster Rugby Score Card | |||||
| Name | Tries | Conv | Pen | Drop | Pts |
|---|---|---|---|---|---|
| Mat Berquist | 1 | 3 | |||
| Total | 1 | 3 | |||
| |||||||||||||||||||||||||||||||
