Sydney, Jan 31 (IANS): India's top batting order put Shane Watson's unbeaten 86-ball 124 in the shade as they clinched the third and final match of their Twenty20 International (T20I) series by seven wickets to blank Australia 3-0 at the Sydney Cricket Ground here on Sunday.

Watson's superb maiden century powered Australia, batting first, to a handsome 197 for five. In reply, India rode on blistering batting from their top four batsmen -- Shikhar Dhawan (26 in nine deliveries), Rohit Sharma (52 in 38), Virat Kohli (50 in 36) and Suresh Raina (49 not out in 38) -- to overtake the target in the final over.

With India needing 17 in the final over, Yuvraj Singh hit pacer Andrew Tye for a six and then a four off the first two deliveries to pave the way for the last-ball heroics by Raina.

Chasing the 198-run target, India got off to a flying start. They raced to 62 in the first five overs, thanks to a quickfire 26 off nine deliveries by Shikhar Dhawan -- who, after a dismal ODI outing, was getting into the groove in T20I. The left-handed opener plundered four fours and a six.

Watson got rid of Dhawan who edged to debuting wicket-keeper Cameron Bancroft.

However, the wicket didn't bring relief for the hosts as the in-form Virat Kohli joined Rohit Sharma in the middle and the duo scored at will.

They forged a 78-run stand for the second wicket when Rohit got out after scoring 52 off 38. The Mumbai right-hander was caught by Watson at midwicket off Cameron Boyce -- but not before putting India strongly on track -- at 124/2 in 12.3 overs.

Later, Kohli completed his 12th T20I fifty -- third in the series -- but soon lost his wicket being bowled by Boyce with India needing 51 runs in 5.1 overs.

Thereafter, Raina kept India going with two back-to-back crucial fours in the 18th over, after which India were short of 22 runs in two overs.

In the penultimate over, Watson bowled brilliantly and gave away only five runs with Yuvraj struggling to hit big.

The veteran southpaw, however, made amends in the final over collecting 10 runs off the first two deliveries bowled by Tye. A bye off the third ball was followed by two consecutive doubles from Raina, who then hit a boundary as against the required two runs for the win.

For Australia, leg-spinner Boyce impressed with figures of 28-2 in four overs, while Man-of-the-Match Watson gave away 30 runs for a single wicket.

Earlier, Watson, making his debut as captain in T20I, milked six sixes -- three off Ravindra Jadeja and two off Ashish Nehra -- and 10 fours during his maiden ton as the Indian bowlers conceded 117 runs in the final 10 overs.

It was also the first time that India gave away a hundred to an opposition batsman in the shortest format.

Trailing 0-2 in the series, Australia came up with the scratch opening pair of Watson and Usman Khawaja as regular batsmen David Warner, Aaron Finch and Steve Smith did not play either due to injury or because they were being rested for the forthcoming series against New Zealand.

The hosts didn't get a good start as in-form Khawaja was dismissed for 14 with the right-hander edging a Nehra delivery to wicket-keeper Mahendra Singh Dhoni in the third over.

However, experienced Watson, dropped from the One-Day International (ODI) series, showed why he is still a force to reckon with as he kept punishing the Indian bowlers.

He played a crucial role in a 50-run partnership with Shaun Marsh, who took his time.

Left-hander Marsh (9) had his stumps shattered when he went for a mistimed slog sweep off off-spinner Ravichandran Ashwin.

Marsh's wicket, with Australia at 69 for two in 7.4 overs, brought 'Big Show' Glenn Maxwell (6) but he was soon holed out at short cover to Suresh Raina off Yuvraj Singh's bowling.

Travis Head then joined Watson in the middle and provided the muscle. He despatched Yuvraj for a six and a four to boost his captain's faith as the partnership flourished, with Watson on a song.

Watson also benefitted from India's generosity. He was batting on 56 and on the second ball of the 12th over, he mishit a wide ball from Hardik Pandya towards Virat Kohli, who spilled the catch at deep cover. In the 14th over, skipper Dhoni failed to collect a throw from Pandya, failing to run Watson out as the batsman tried to complete his second run.

Watson made India pay as he hit two sixes off left-arm spinner Jadeja and one off Ashwin before completing his maiden hundred in 58 balls.

After the hundred, he again hit Jadeja for a six and one off Nehra as his team mustered a total of 197 for five.

Kohli got the Man-of-the-Series award for scoring 199 runs in three matches.