Keith Earls struck the decisive blow at Thomond Park as Munster ended a four-match losing run against rivals Leinster.

Ian Madigan and Ian Keatley traded blows with the boot, but it was Earls’ first-half try – while Madigan sat in the sin-bin – that proved the difference between the two sides.

Leinster won an early penalty, after just three minutes when the hosts failed to release in the ruck, which Madigan kicked confidently from in front of the posts.

Munster flew back at the visitors in an unsurprisingly feisty opening, which led referee Romain Poite to fire an early disciplinary warning at Leinster skipper Jamie Heaslip.

Donnacha Ryan broke into the visitors’ half after ten minutes but an efficient turnover, clearance and added pressure from Leinster forced Keatley into a rushed kick, straight into touch.

Munster’s pack dominated the early exchanges and it earned a penalty and the opportunity for Keatley to draw them level, but his kick hit the post in the 14^th minute.

Another electric Munster break saw Earls offload to James Downey, who streaked into the opposition half but the visitors once again turned it over and eventually were awarded a penalty.

Madigan opted to go for the posts but his halfway-line effort fell narrowly short of doubling the Leinster lead.

But the visiting fly-half didn’t miss the opportunity for another three points after 24 minutes, sending his second penalty through the posts.

Six minutes later it was Keatley’s turn to make amends, after further ill-discipline in the ruck, and he slotted a penalty from 35 yards to get the Munstermen on the board.

Keatley then made a streaking break from inside his own half before kicking a neat grubber, which was cut out well by Dave Kearney, but Madigan callously hacked the ball away and was sent to the sin bin for the remainder of the half.

From the resulting lineout Keatley sent a majestic cross-field kick to the right wing where Earls was waiting to collect and cross over on 33 minutes – Keatley duly converted.

Munster’s enthusiasm didn’t waiver but it cost them a series of penalties, the last of which came for Niall Ronan entering a maul from the side and Fergus McFadden deputised in Madigan’s absence to pick up three points on the stroke of half time.

Munster kicked off the second half with another Keatley penalty, which he slotted from 40 yards, to make it 13-9 before Madigan returned to the pitch.

With a full compliment back on the pitch Leinster began to have a greater influence but a driven Munster back line kept them at bay – until Paul O’Connell was penalised for entering a maul from the side.

Madigan sent a very straightforward kick through the posts before a soft penalty on 55 minutes gave him the chance to restore Leinster’s lead, which he did.

But Keatley re-took the lead for Munster just two minutes later, as this heated clash continued to produce plenty of penalties – he slotted another tricky one on 63 minutes to earn the hosts some breathing space.

Neither side showed any sign of taking a breather, as Lote Tuqiri and Rob Kearney each broke the Munster line but the hosts showed tremendous resolve.

Casey Laulala was next to make a line-breaking run but he was held up just short of the Leinster line – the Munstermen kept probing but Tuqiri led a breakaway to relieve some pressure.

Keatley missed the opportunity to put further daylight between the two sides three minutes from time, but it wouldn’t prove costly as the Munstermen crept over the line.