The Rams needed a last-ditch winner from Conor Sammon to see off Boro, and the former England boss claims that the performance was not up to their usual standards.
"It's three points," Sky Sports News quotes McClaren as saying. "That's it. It was not a good performance by our normal standards.
"We talk about getting a performance and the result will follow. The Championship is tough and there are different ways you have to win. We won it despite not playing our usual brand of football and we were disappointing in that."
However, McClaren went on to refute suggestions that his team were lucky to come away with maximum points.
"I wouldn't say we were lucky as we kept our patience," he added. "If we were going to achieve anything or deserve to be in the position we're in, then we have to score in the last 10 minutes.
"We waited for the moment and took it. They're the kinds of things teams have if they're going to be successful."
The result leaves Derby in fourth place in the Championship table with 31 points from 18 matches played.