The England forward bagged his eight goal of the campaign - and the 100th of his career - with a shot that struck the underside of the crossbar, sealing the points for the champions.
“It was a really good moment, especially at 2-1 to make it 3-1- it was a really nice feeling," said Sterling.
“I had chance earlier on and didn't know was onside until I dragged it wide - you just have to stay focused.
“I was running into the box, but thinking Riyad couldn't make that pass, but it went through the defender's leg, I took it early and I didn't get enough on it.
“I knew another chance would come. I was waiting for an opportunity and it eventually came.
“But you have to finish chances like that off because in the Premier League you can be punished."