"The man with the whistle didn't make it was for us and was pretty pedantic. We couldn't get any quick ball," admitted Wales head coach Warren Gatland.
"With a team with that much possession the penalty count shouldn't have been 13. The Yellow Card was pretty tough as well - Leigh jumped for the ball and not to take the player out.
"The boys are a bit flat in the dressing room but we are happy with having four wins from four. They wanted to score some points today and that's why they are frustrated - the game turned into a dog fight."
But despite the frustration at only scoring two tries, Wales will be shooting for an 11th Grand Slam next week when Rugby World Cup runners-up France come to Cardiff for a game that will replicate the World Cup semi-final in Auckland earlier in the season.
"We have got a chance of completing a third Grand Slam in eight season. We are at home again next week and we will try to keep our heads down - if we do achieve a Grand Slam it will be a bit special," said Gatland.
"This team has honesty and a strong work ethic. Putting on the red jersey means an awful lot to them. That has a significant impact on them mentally. They are all aware of the history of Wales.
"I don't think it will be difficult for us to keep a lid on things next week. We have planned next week so that we aren't out too much. These young players are taking things in their stride.
"The welcome we had from the fans as we drove into the Millennium Stadium was fantastic. The players are well aware there will be a huge crowd and huge hype next week. We are in a good place and the Welsh public seem to be pretty pleased with the players."