MELBOURNE (Agencies) - ICHAEL Clarke, refreshed "mentally and physically" after a few days away from cricket, will step into Ricky Ponting's boots as captain and No.3 batsman against England at the MCG. Clarke, who retired from Twenty20 cricket after a dismal Ashes campaign, said he spent a couple of days relaxing before flying into Melbourne on Friday morning for a net session. He is excited about Australia's opening 50-over match, the first of seven in the Commonwealth Bank series, as it celebrates the 40th anniversary of the first one-day international. And he is looking for a series win to build momentum to next month's World Cup on the sub-continent, a tournament that Australia has made its own with three consecutive wins. Clarke said his leadership would not be compromised by any obligation to give World Cup hopefuls - including speedsters Brett Lee and Shaun Tait - maximum opportunities to press for inclusion in the Cup squad, which will be trimmed from 30 to 15 on Wednesday. "It may be the last opportunity to impress for some of the blokes in this opening game, but our aim is to win every game, win the series, and gain momentum for the World Cup. I'll just let it unfold," he said. The official World Cup squad of 15 will contest the remaining six matches of this tournament. And Clarke indicated that David Hussey could be an integral part of World Cup calculations. "It may be that having Shaun Tait, Brett Lee and Mitchell Johnson - who can take wickets and tie up the runs when the new ball is older (it is hard to start your innings against balls coming at you at 140-plus km/h) - is workable with others to make up the remaining overs. "We have Shane Watson, and David Hussey adds to our bowling, especially on pitches that take spin."He could be important for his bowling as well as his batting and fielding," Clarke said. England skipper Andrew Strauss, also refreshed after a short break, said playing Australia in this seven-match series would give the team a solid foundation for the WC. "Australia is No 1 in the world in this type of game. Both sides will be very much up for this series, and we understand the size of the challenge ahead of us. "I think we have an excellent chance to win the World Cup. We have improved dramatically over the past 18 months with our attention to detail, and a couple of our guys are in decent nick," he said. England will regain ace paceman James Anderson after the opening three matches of the Commonwealth Bank series. Squads: AUSTRALIA: Shane Watson, Brad Haddin, Michael Clarke, David Hussey, Michael Hussey, Cameron White, Steve Smith, Doug Bollinger, Mitchell Johnson, Peter Siddle, Shaun Tait and Brett Lee, Xavier Doherty. Nathan Hauritz has been released from the squad. ENGLAND: Andrew Strauss, Steve Davies, Kevin Pietersen, Ian Bell, Collingwood, Eion Morgan, Jonathan Trott, Graeme Swann, Michael Yardy, James Tredwell, Luke Wright, Tremblett, Ajmal Shahzad, Tim Bresnan, Chris Woakes, Steven Finn.