Watson, continuing his good form that enabled him to score over 800 runs in the 2010-11 season, started on a cautious note before opening up to score a well-crafted 79 off 92 balls, after Ricky Ponting opted to bat first at the Sardar Patel Stadium.
He was also involved in two half-century stands, of 61 with fellow-opener Brad Haddin (29), and 79 off 75 balls with Ponting (28). But his dismissal in the 32nd over, followed by that of his captain almost immediately, somewhat spoilt Australia`s plan.
The pair was dismissed in the space of nine balls and it was then left to Michael Clarke, who made an unbeaten 58 in 55 balls, and the lower order batsmen to give the Australian innings a boost.
Vice captain Clarke, who struck four fours, and Cameron White (22), who was dropped on 15, set about the task after the departure of Watson and Ponting. They raised 63 runs in 73 balls, including 32 during the batting powerplay taken between 41st and 45th over.
Their fourth-wicket stand yielded 63 runs off 73 balls.
Clarke looked at ease in his unbeaten knock as Australia finally set their rivals, to whom they have lost just once in 27 previous meetings, an asking rate of 5.26 to win the match under lights.
The Aussies, bidding for their fifth world crown and fourth in a row, commenced the title defence on a sedate note, with the first ten overs producing only 28 runs on a wicket that looked slow and offered low bounce.
Openers Watson and Brad Haddin seemed content to play the waiting game against the pace-spin opening duo of Chris Mpofu and Ray Price, the left arm slow bowler.
It was spin from both ends, when Zimbabwe skipper Elton Chigumbara replaced Mpofu, who conceded just 13 runs in his first five overs, with off spinner Prosper Utseya.
The Australian opening pair struggled to score freely against the two spinners, and Haddin was even lucky to have got a reprieve on 16. An Utseya delivery struck the bottom of the middle stump but the bails were not disturbed.
The run rate improved when Mpofu came on for his second spell, with the Australian pair hitting the medium pacer for two boundaries each. At the end of the batting powerplay, Australia were 53 without loss.
Utseya got his revenge when he trapped Haddin in a dramatic fashion. Umpire Asoka de Silva thought that`s not out, but the Decision Review System came to Zimbabwe?s aid.
Watson Ponting then went about rebuilding the innings with a stand of 79 before DRS again helped the African nation after the original decision of umpire Richard Kettleborough helped the beefy opener.