Melbourne, Jan 12: Ahead of the five-match ODI rubber against Australia, starting on Sunday, English top-order batsman Jos Buttler on Thursday rated the tours of India and Australia as the toughest challenges for his side. Buttler, who is also the vice captain of the 50-over side, feels the One-day International series, starting at the Melbourne Cricket Ground will be a "great test" for the Englishmen, who were humiliated 0-4 in the preceding Ashes Test rubber. "Coming here and going away to India are the two biggest challenges for us in the last few years. Massive challenges for us and exciting ones," Buttler was quoted as saying by ecb.co.uk. "The Australians became the world champions here at the MCG three years ago, so it will be a great test for us as a side. But the swashbuckling batsman is confident of turning things around in coloured outfit and indicated that they will stick to their own game plans in the series. "We won't be trying to change much with the way we play. You got to be smart and adaptable to the conditions and try to play the type of cricket we normally play," he said. After the opener at the MCG, the visitors will play the second ODI in Brisbane on January 19, followed by the third game in Sydney on January 21. The final two games will be played at Adelaide (January 26) and Perth (January 28). The ODI rubber between Australia and England will be followed by a T20I tri-series also involving New Zealand.