Harbhajan collected five for 147 from 44 overs and his performance continues to fuel the debate about his exclusion from the first two Tests that both ended in tense draws with the West Indies holding on for dear life.
The patka-wearing off-spin bowler was surprisingly omitted from the Indian side for the first two Tests of the series at St. John's and Gros Islet, but he was the most successful bowler for the visitors in a West Indies first innings total of 581.
"I don't know if this performance showed that I should have been selected for the first two Tests, but it's always tough to sit out, and difficult to see the matches from the outside," he said.
"You learn a lot when you sit out. When you watch cricket, you still pick up a few things which can be important for you. I wanted to get back in the first 11. I got my chance to play here, and I am very happy to be playing."
Harbhajan collected the last four West Indies wickets, as the home team lost their last five wickets for 19 runs in the space of 33 balls.
It was something of a comeback for Harbhajan, after the top-order batsmen of the West Indies had severely punished him over the first two days of the Test.
"When you go for some runs in the beginning, it's always tough to come back in the match," he said.
"I'm really happy with my efforts, but I know I can do better than this. It is all part of a learning process and I'm still learning. Hopefully, in the future, I'll be able to do better than what I've done and what I've achieved so far."
Harbhajan added that the Warner Park pitch reminded him of the surface at Lahore in Pakistan.
"It's very flat," he said. "You just have to hit the right line and length. You just have to be patient and keep working hard.
"You have to keep talking to yourself. You have to be brave enough to put the ball in the right spot, give the ball a little bit of air. If you are brave enough, you will get wickets on any sort of track."
India were 150 for two when stumps were drawn and need 232 more runs to avoid the follow-on.