The Croatia international was on the scoresheet for the first time since December last year, netting the opener at the Estadio Nuevo Los Carmenes.
Rakitic also set up Luis Suarez's goal to make it 2-0, and said it was good to contribute in a big way to his side's victory.
"When you score and make an assist you feel better, but I have always felt good here," he was quoted as saying by Barcelona's website.
The win moved Barca back within a point of La Liga leaders Real Madrid, who host Villarreal on Sunday.
Rakitic, 26, said it was a key victory and believes his team were deserved winners – with Lionel Messi sealing the three points after Granada had pulled a goal back.
"It is important to keep getting points," he said.
"It was a very difficult match and Granada created a lot of problems for us, but we did a good job and I think we deserved the win.
"The pitch wasn't easy to play on but we managed to make our identity show and worked hard from start to finish. We have to keep improving but we’re on the right track."
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