Dimitar Berbatov celebrated his 32nd birthday with a vital - if offside - opening goal, although Kevin Nolan levelled for the visitors at the start of the second half.
"The result was very important," Jol said. "It was a vital, vital win.
"They were on 27 points, we had 25. Norwich were on 26 so it is a vital win.
"I am a happy customer, especially is you saw this game and the last four games here at home.
"We lacked a bit of luck, sometimes a bit of quality and today the first half we were good.
"We were happy to score that goal, although I've heard it was irregular but I am not sure.
"Maybe it was offside but I can remember a couple of moments this season when we had the same decisions against us so, as you say in England, you win some, you lose some.
"Hopefully today we won some and that was probably the case with the first goal."