The Super League giants won 54-4 at Tetley’s Stadium two days ago, after leading 36-4 at the interval.
Morrison said: “They started strongly and probably caught us off guard a bit.
“We were lazy on the inside defensively and we got caught a few times.
“They targeted our right-edge, which has been leaking a few points and we also had a youngster making his debut for us.
“But we managed to dig in after that.
“We only conceded three tries in the second half, we made plenty of line-breaks and we tested them out.
“We were unlucky not to score a few tries and in that sense I was proud of the boys and they way they didn’t let it go on to be a cricket score.”
Debutant Donald Kudangirana had a torrid opening to his senior career as Wigan raced 24-0 ahead, but Morrison said: “They scored four quick tries, but after that he came in looking for work and he could hold his head up high.”
Rams came through with no major injuries, which was a positive for Morrison ahead of Saturday’s crunch trip to Whitehaven in the Kingstone Press Championship.