Clinical hosts hand Ireland a hammering
McNamara had accused his players of taking their eye off the ball in a shock pre-tournament defeat by Italy but this time they looked fully focused from the start as they established a 30-0 lead after 23 minutes.
Ryan Hall led the way with three of his side's eight tries and fellow winger Tom Briscoe made the most of his recall to the side by touching down twice, while Kallum Watkins, Rangi Chase and Brett Ferres added others.
"Overall I'm pretty pleased," McNamara said. "We hit a real purple patch in the first half when we played with some great shape and executed some nice stuff.
"To nil any team, particularly at international level, is a credit to the players. We weren't as fluent in the second half when the conditions were worse but we showed a bit of grit to keep them out and it bodes well."
England scored just 12 points in the last 57 minutes and captain Kevin Sinfield admitted the swirling wind and rain played a part in that.
"In the second half with the driving rain it affected how we played," he said. "We had to tighten things up."
Huddersfield duo Ferres and Leroy Cudjoe looked perfectly at home in familiar surroundings. They combined effectively twice in the first 12 minutes to get Hall over for two of the easiest tries he will surely ever score for his country – which enabled him to draw level with Sam Tomkins as England's all-time leading scorer before quickly overtaking him with his hat-trick try.
Hall was named man of the match after taking his try tally for England to 17 in as many matches but he played down his role in the victory. "I've scored a lot of tries but wouldn't have got any if it wasn't for my team-mates," he said.
After being the architect for two of Hall's tries, Cudjoe looks to have cemented his spot in the England threequarter line. McNamara said: "If you look at the outside backs, the quality and speed is there for all to see.
"They are all really young men as well. They've gained valuable experience over the last two years and it's really exciting for now."
McNamara will check on the fitness of prop forwards George Burgess and James Graham after they both came off with injuries.
England will now need to beat Fiji in Hull next Saturday to secure second place in the group, while Ireland must pull off an unlikely win over tournament favourites Australia in Limerick to keep their dream alive.
Ireland coach Mark Aston said: "We got a bit of an education in how to play a game of rugby league but I was immensely proud of the boys in the second half.
"For a large spell in the game we were very competitive but, if you make mistakes and give penalties away, they can hurt you. They asked questions and at times we couldn't answer them.
"We've got something to build on. We'll dust ourselves down because we've got another challenge next week against Australia. It's a tough group but I think we've come out of the first two games with pride and it will stand us in good stead."