The 39-year-old, who scored the second goal at Loftus Road, said that the Red Devils were aware of the danger posed by the relegation battlers before the game.
However, the Welshman feels that his team were "comfortable" in seeing out an important victory that sees them got 15 points clear at the top of the table.
"We are in a tremendous position," Giggs told BBC Sport. "We had to dig in today to get that important 15-point lead and we are really pleased.
"We knew it was going to be difficult; they are fighting for their lives, so it was tough.
"At 1-0 you never know how it's going to go, especially with the quality they have up front, but at 2-0 we kept the ball better and it was comfortable."
Giggs also praised Brazilian full-back Rafael for his stunning opener in West London.
"I have to say Rafael's goal was one of the best goals you are going to see and in the second half we got better," he added.
"He really deserves it, he's been brilliant, really consistent, and it tops off a good season for him."
Second-place Manchester City take on Chelsea at the Etihad Stadium tomorrow.