I've affected changes to his game and improved his shot selection over the last six months, the Tamil Nadu wicketkeeper-batsman said in an interview to a Sport's magazine,
''I've always been an extremely positive batsman and my strike-rate in Ranji games has always been close to 100. It resulted in some rash shots, costing me my wicket after a start.
Over the last six months or so, I've become much better in that aspect,'' said the 22-year-old right handed batsman.
Often praised for his quick reflex action behind the stumps, Karthick, with 11 Tests and eight ODIs under his belt, was chosen as a specialist batsman in South Africa and he responded magnificently with three important innings - a match-winning 31 not out in the Twenty20, 63 on the opening day of the third Test and 38 not out in the second.
He had also batted wonderfully in the four-match home ODI series against the West Indies last month and was today included in the Indian team to face Sri Lanka.
Karthick, however, admitted that he was probably too aggressive in his early games for India.
''In my first stint with the Indian team, I was probably over-positive. In Bangladesh, in both innings I got out to cut shots. I hit six fours in my 25 at Dhaka but didn't carry on. At Chittagong, I was trying to hit over the top when I was on 11. I don't think I will bat like that now.
''A lot of people think being positive is playing aggressive shots and hitting over the top.
''But I've realised you can be very positive with your defence as well -- going fully forward, leaving the ball correctly, judging the line. If I can get to defend with the middle of the bat, if I can leave with confidence, I see myself as being positive. That's all I try to do in all my innings -- looking positive and at the same time playing correctly,'' he said of change in shot-making to adapt his game.
Despite his recent success with the willow, Karthick refuses to even think of leaving wicket-keeping.
''I usually bat well when I'm keeping well, it's a matter of confidence. I will definitely be keeping in domestic cricket,'' said the Tamil Nadu player.
Bharat Arun, who had closely followed Karthick's development also did not think he'll ever give up his wicket-keeping, even if chosen as a specialist batsman, because ''he's (Karthick) so eager to work on all aspects.''
''He's always been a cricket freak. You can never stop him from working at his game, how much ever you try. If he's working on his fitness, he can go on all day,'' Arun, former Tamil Nadu all-rounder who played two Tests for India in the mid-eighties, said.
''If he wants to improve in a particular area, he gets obsessive. I've seen him practice 200 reverse sweeps in a session, such is his passion. Even when he was a wicketkeeper, he used to practice his fielding - that's why he's such a good slider.''
Although billed as rivals for one place in the national side, Karthick said he enjoyed a healthy rapport with Mahendra Singh Dhoni.
''A lot of people know Dhoni as a flamboyant batsman, but in his life outside cricket, he's a very nice person."
''He's someone who you can approach and talk to about anything in life. He's very quiet, goes and sits in the last seat in the bus, doesn't interfere with anything. He doesn't say much in team meetings, but whatever he says makes a lot of sense,'' Karthick said of Dhoni.