Senior off-spinner Harbhajan Singh reckons that comebacks are always "tough at Test level" but the veteran of 99 Tests is hopeful that he would be able to make a difference in the upcoming Test series against Australia.

"Comebacks are always tough. As long as you continue to work hard and believe you can make a difference and do well in international cricket, you can make a comeback," Harbhajan told mediapersons at the post-match conference of the Irani Cup today.

"I am very happy to be back in the Test squad and hopefully, I can make the difference there," said Harbhajan, whose last Test before this series was against England at the Wankhede Stadium.

Harbhajan, who has been pretty good at playing mindgames, said that a number of left-handers in the opposition squad could work to India's advantage.

"It's always nice to play against Australia. They have a pretty new batting line-up. If I am not wrong they have a lot of left-handers, apart from (Michael) Clarke and (Shane) Watson and they have not played much Test cricket and not played in India.

"This would be a challenging series for them and hopefully we will put them under pressure from the first day of the Test match."

Having been out in the wilderness for the better part of the last 18 months, Harbhajan said that he has been qworking very hard on his game at the domestic level.

"When you are playing Ranji Trophy constantly sometimes you may take wickets and sometimes you may not. But I have been working very hard on my game and trying to give everything I have every day.

"A new day gives you a new opportunity. That's what I have kept telling myself that I am still good enough to play for India and that's the reason I have been playing cricket."