Shane Watson smacked a big century as Australia cruised to a comfortable seven-wicket victory in Grenada on Sunday to clinch their five-game series against the West Indies 3-0.

Watson's blistering 126 helped Australia to stroll to 227-3 and victory after restricting West Indies to just 223 in the third one-dayer of the series.

Skipper Ricky Ponting also hit a brisk 69 in Australia's run chase, while Nathan Bracken took three wickets to stifle the home side's batting after a bright start.

Home skipper Chris Gayle had earlier given their innings a good start as he hit 53 including his 100th six in ODI crickets - just the third West Indian to achieve that feat.

Ponting's men now hold an unassailable 3-0 lead in the five-match series after another convincing win against the Caribbeans - who now just have pride to play for in the remaining two matches in St Kitts.

The hosts were sent in to bat in St George's by the Australians, and they started well as Gayle and Xavier Marshall produced a promising opening stand of 86.

Gayle was run out for 53 from just 54 balls and Marshall followed quickly for 35 when Watson made his mark with the ball to get the batsman caught behind.

Ramnaresh Sarwan and Shivnarine Chanderpaul added 61 for the third wicket but they both went quickly for 31 and 32 respectively and the Windies were stuttering at 168-4.

Bracken then got rid of Andre Fletcher and Denesh Ramdin as wickets continued to tumble and the hosts were eventually all out for 223 with two overs of their 50 still remaining.

Australia would have fancied their chances in their run chase, but they suffered an early setback when Shaun Marsh was bowled by Fidel Edwards for nought with just one run on the board.

Watson and Ponting did not panic though, and soon they set about smashing Australia towards their target in what turned out to be an immense partnership of 190.

Ponting made 69 from his 83 balls with seven fours before he was caught off Gayle's spin bowling, but Watson kept on his attack.

Watson eventually departed after smashing 126 runs from 122 balls, with 15 fours and two sixes and with Australia coasting on 207-3.

Michael Clarke and Andrew Symonds were left with the simple task of guiding the Aussies to the finish line, which they made when the score ticked on to 227-3 with nine and a half overs still left to bowl.