Replacements Tommy O'Donnell, Barry Murphy and Lifeimi Mafi all touched down in the final eight minutes of a topsy-turvy Magners League derby.

However, the gloss was taken off the bonus point win by the sight of Jerry Flannery limping off late on after another attempted comeback from a troublesome calf injury.

In wet conditions, Ulster stole an early march on their provincial rivals with a Thomas Anderson try and five points from the boot of Paddy Wallace.

Trailing 10-6 at half-time, Munster clawed their way back through the boot of Paul Warwick and a Denis Hurley try.

The league leaders upped the tempo as a tiring Ulster lost Neil McComb to the sin-bin, and the late hat-trick settled the issue.

A crisp strike from Warwick towards the right corner put Ulster under immediate pressure, but Munster could not make use of the early territory.

Warwick miscued a penalty to the left of the posts, and some good continuity from Paul Marshall and the Ulster forwards was rewarded by Wallace's well-struck opener in the tenth minute.

Munster's midfield was sliced wide open two minutes later by a sidestepping Tommy Seymour and he was able to link with Willie Faloon before Anderson fended off Peter Stringer on the way to the try-line.

It was a superbly executed try, exposing some poor defending from the hosts and Wallace added the extras for a 10-0 scoreline.

Warwick kicked one of two penalty attempts as Munster upped the intensity, yet Ulster, led by fit-again captain Rory Best, continued to carry more of an attacking threat.

Scrum half Marshall was a livewire throughout, and his 30-metre burst from the back of a ruck almost resulted in a try. Munster survived and some Ulster indiscipline offered them a welcome slice of territory.

Warwick was back on target from a 32nd minute penalty, and Wallace could not add to Ulster's tally as his late penalty attempt went to the right of the target.

A series of pick-and-go drives from the home forwards set up Warwick for a three-pointer from close range, early in the second half, and Munster finally found another gear.

Sam Tuitupou and Keith Earls sprung Scott Deasy through a gap and over halfway, Munster maintained possession and Warwick's looping pass sent Hurley in at the left corner.

Cue the introduction of hooker Flannery, back for the first time since October, and after Ulster replacement McComb was sin-binned for illegally bringing down a maul, the hosts began to dominate.

Denis Leamy was held up over the try-line and just when a penalty try was looming, an early engagement at a five-metre scrum saw Munster blow a huge opportunity.

Earls was hauled down short of the line by Chris Henry, but the forwards piled in and O'Donnell crossed from close range. Warwick's conversion made the game safe at 21-10.

Ulster threw caution to the wind and after Marshall lost possession from a tap penalty, Murphy was able to hack the ball on three times before dotting down for his try.

Doug Howlett earned a yellow card for hands in the ruck in the dying minutes, and an injury-time counter attack, sparked by an Earls burst and carried on by Murphy and Donnacha Ryan, was finished by Mafi for the bonus point score.