Things would have been tighter for them had Munster not had two tries disallowed for earlier knock-ons. Visiting fly-half Paul Warwick also missed three penalty kicks in the opening half and they proved crucial as the Irish province were left trailing by 13-0 at half-time.

It was the two tries from Byrne and Williams that did the damage as the Ospreys claimed their second win in three league games. Bolstered by the return of their Welsh internationals, the hosts suffered an early blow when centre Gavin Henson took a knee in the back and had to be replaced in the 13th-minute.

By that stage, they were already 3-0 in front thanks to a fourth-minute penalty. With their pack performing well, Munster were drawing errors from their opponents, yet Warwick's misses after 2, 8 and 22 minutes - one of which hit a post - left them frustrated.

Tighthead prop Tony Buckley's try-scoring celebrations were also premature as having crashed over the Ospreys' whitewash, he was disappointingly called back for an earlier knock-on.

Television match official Hugh Watkins was then called on to rule out an effort from Mike Phillips, who was making his home debut for the Ospreys. The Wales scrum half had been held up over the try line by Munster winger Ian Dowling.

But on the half-hour mark, Byrne had his try rubberstamped by Watkins after the Ospreys full-back's momentum had taken him over the line.

The score went unconverted as did Williams' touchdown three minutes later, which saw the diminutive number 11 squeeze in at the right corner after a timely offload from Byrne. TMO Watkins confirmed the try.

Having missed both conversions from difficult angles, the 18-year-old Owen regained his place-kicking poise eight minutes after the break when he punched a penalty through the posts for a 16-0 Ospreys lead.

With their hopes of a first ever away league win over the Ospreys fading fast, Munster dipped into their reserves and brought on Ireland World Cup players Peter Stringer and Frankie Sheahan.

The men in red did manage to get off the mark in the 55th-minute when replacement fly-half Jeremy Manning landed a penalty after Owen had been yellow carded for killing the ball at a ruck.

However, Munster failed to seize their chance while the home side were down to 14 men. The Ospreys' defence was resolute, with Wales caretaker coach Nigel Davies and defence coach Rowland Phillips watching on from the stands.

It was all too evident that this was not going to be the Irishmen's day when Manning was denied a try in the right corner by a knock-on at the preceding ruck, leaving Lyn Jones' side to comfortably see out an encouraging victory.