The result saw his side move six points clear of Wigan Athletic in the relegation battle and Lambert admitted to relief at the final whistle.
"Some of the football we played was excellent, it was some game that," BBC Sport quotes Lambert as saying.
"I thought we could create and the goal before half time was terrific. It was credit to QPR as they came at us really strongly. I was delighted to see it through.
"Last week's win was huge, and the atmosphere today was electric."
QPR remain bottom on 23 points.