England made 294 all out in 49.4 overs, Kevin Pietersen top-scoring with 78. Watson wrapped up the win by scoring a six with five balls to spare as the hosts ended on 297-4.
The second game in a seven-match series is in Hobart on Jan. 21. England has already won a Test series 3-1, and a Twenty20 series was drawn 1-1.
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