Keane has scored one goal from his opening two games for Tony Mowbray's side and is backing himself to score for fun when his fitness improves.
The 29-year-old admits he is a life-long Celtic fan, but that he will return to White Hart Lane in the summer when his loan spell ends.
"I decided to come up here because it's a massive club and a team that growing up in Ireland you're almost born into being a Celtic fan," he told Sky Sports.
"I've been in the Premier League for a long time. I've done what I needed to do there. I'm here for a few months and obviously I'll be back there next season.
"I'm a person that needs to play all the time. I get better with games. The more games I get under my belt and the more 90 minutes I play, you'll see a sharper and fitter Robbie Keane."
Keane admits the hype of his loan arrival has only served to intensify the pressure on his shoulders, although he insists that it will not impact upon his form.
"As a striker there's always pressure. You need to score goals," he continued. "The hype of me coming up here adds to the pressure as well.
"One man doesn't make a team. The most important thing is the team.
"I'm here to help the team and hopefully push on and challenge to win that title. By no means is it going to be easy, but it's not impossible."
Scottish Premier Winner 2009/10 Win Outright: Celtic 7/2