* Scotland still without a win
* Coach upset with referee on sin-bin issue
* Three tries for Ireland
Ireland ran in three tries to set up a 21-18 victory over Scotland in their Six Nations clash at Murrayfield on Sunday.
The result left the Scots still without a point from three games. Ireland joined Wales and France on four points, two behind leaders England.
Ireland led 21-9 midway through the second half when they looked capable of stretching their advantage.
But a lack of discipline enabled Scotland to close the gap to three points, largely through the boot of Chris Paterson.
Scotland coach Andy Robinson was bitterly disappointed with referee Nigel Owens, criticising the Welsh official over his failure to sin-bin any Irish players, despite the fact they gave away 13 penalties against Scotland's four.
Scotland prop Allan Jacobsen was the only player sin-binned and Robinson said: "I thought it was a major turning point of the game when we were about to get on top of the Irish.
"I have a number of issues with the high Irish penalty count and no sin-bins for them. Their ability to slow the ball down is illegal."
While the Scots finished strongly, it had started to go wrong for them from the sixth minute when they conceded an early try for the fourth match in succession.
Jamie Heaslip was the scorer and his off-load 22 minutes later presented Eoin Reddan with Ireland's second.
Ronan O'Gara converted them both but Scotland were able to stay in touch before the interval as Ireland's indiscipline gave Paterson the chance to kick three penalties.
Ireland's 14-9 lead did not reflect the extra imagination and purpose they had displayed but the scoreline was given a more realistic look when they exposed Scotland's defence again while Jacobsen was in the sin-bin.
O'Gara broke through a tackle by Paterson to score the visitors' third try in the 53rd minute and then converted for the 12-point cushion.
Paterson reduced the deficit by kicking two penalties in quick succession and Ireland's lead was down to three points when Dan Parks added a drop goal.
It left Ireland facing a difficult final 10 minutes, but they held out for victory.
Ireland coach Declan Kidney said: "I have no intention of getting into a slanging match about the referee. It's a very difficult job.
"I thought the 31 people on the pitch put in a decent effort and it is important to work to that.
"It was edge of the seat stuff at the end. I thought we did well to get three tries, but probably didn't do so well in allowing Scotland to come back into it."