Sourav Ganguly has hailed MS Dhoni as a 'champion' but had an important and timely advice for his fellow former India captain before the India-Australia ODI series.

MS Dhoni will have his task cut out for him when joins the Indian team down under for the ODI series against Australia early next year.

MS Dhoni, who has retired from Test cricket, was not included in the team for the T20I series. Rishabh Pant who replaced him in the T20Is will be India's primary choice for the Test series too following the injury of Wriddhiman Saha.

While it's not yet confirmed, Dhoni is expected to be part of the ODI side for the three-match series starting January 12. However, Dhoni will be under heavy scrutiny in the series given his recent below average form and the upcoming 50-over world cup.

Echoing these same sentiments, Sourav Ganguly also said that Dhoni must perform in the series.

"Just like everyone else he has to perform. There's one must in life: whatever job you do, wherever you are, whatever age you have, how much experience you have, you have to keep performing at the top level otherwise someone else will take your place," Ganguly said.

"I wish him (Dhoni) all the luck because we want champions to go on a high, whenever he goes. I still feel he can hit the ball in the stands. He's a phenomenal cricketer," he added.

Dhoni has not been his usual self and many have argued for someone younger to replace him in the team. This year, Dhoni has scored only 275 runs in 13 innings at an average of 25.00 with a highest score of just 42 in one-day internationals. However, his experience and presence behind the stumps could be key for India in the 2019 World Cup.