Wales boss Warren Gatland says Scotland fly-half Finn Russell could have been red carded for upending Dan Biggar in the visitors' 26-23 win in Edinburgh.
Russell received a yellow for the challenge in a match of controversial decisions by referee Glen Jackson.
Wales had Jonathan Davies sin binned after competing with Johnnie Beattie five minutes after Russell's card.
"My initial reaction was the first was red and the second was yellow. Those were my gut feelings," Gatland said.
"But I'm looking at it from a Welsh perspective. The referee's got to make the call and you have to live with the decision and move on."
As well as controversy over the yellow cards, Jackson appeared to end the Six Nations match early after Jon Welsh scored a late try for Scotland.
While Scotland coach Vern Cotter declined to comment on the officiating - although said his team would send a report to the officials with their observations - Gatland was philosophical about the referee's performance.
"Both sides felt there were some decisions that went their way, and one or two didn't," said Gatland.
"At this level it's difficult, you've got to back the judgement of the referee.
"I understand that the Scots would have been aggrieved on a couple of calls, the same as us. It was a tough, competitive game."
Wales captain Sam Warburton admitted his team were preparing to re-start the match after Russell's conversion of Welsh's last-minute try, with the Scots needing a penalty or drop-goal to draw the match, and a try to win.
The match clock showed three seconds remaining when the conversion went over, but Jackson blew the final whistle after consulting with the official time-keeper.
"We were chatting about what our next kick-off was going to be, and the best chance of us keeping Scotland out or retaining possession," said Warburton.
"So we were ready for that kick-off, but I wasn't going to complain when we heard that final whistle."
|4 (1)||Scrums won (lost)||4 (0)|
|11 (2)||Line-outs won (lost)||8 (3)|
|73 (5)||Rucks/mauls won (lost)||85 (5)|
|120 (9)||Tackles made (missed)||110 (13)|
|Provided by Accenture|
Gatland believed his side deserved to win at Murrayfield after their opening weekend defeat by England, but admitted it was closer than he would have liked.
"A win is a win in this competition," said Gatland, who has guided Wales to eight straight wins over the Scots.
"It was a big improvement on last week. I thought we went out there and played a bit of rugby.
"We kept the ball in hand and moved Scotland around and that's when we looked dangerous.
"But in fairness to Scotland they competed pretty hard stuck to it, and I've spoken to the players and they say that's the toughest Scotland team they have played for the last few years."
Wales face France next in Paris on Saturday, 28 February.