Afridi prepares to hammer one during the tri-series one-dayer against Australia in Hobart on Sunday. (AFP)

Melbourne: Michael Clarke hit a superb 97 before Darren Lehmann?s 49 not out guided Australia to a four-wicket win in their triangular one-day series match against Pakistan on Sunday.

Earlier, Shahid Afridi smashed 56 not out from 26 balls to lift Pakistan to 272 for seven in 50 overs, after good knocks from captain Inzamam-ul Haq (68) and opener Salman Butt (61).

Following a mid-innings rain delay of just over half-an-hour, Australia?s victory target was revised to 253 in 45 overs.

Lehmann hit the winning runs with two overs to spare at Bellerive Oval in Hobart as the home side reached 253 for six in 43 overs.

Australia had appeared in some trouble at 186 for five in the 33rd over but Lehmann combined with wicketkeeper Brad Haddin (30) for a steadying 57-run partnership.

Pakistan began poorly with Kamran Akmal falling to Glenn McGrath for five and Mohammed Hafeez out to the express pace of Brett Lee for a duck.

Shoaib Malik (31) and Butt added 53 for the third wicket before Malik was leg before to Andrew Symonds.

Butt struck eight boundaries but the left-hander mis-timed an attempted cut off left-arm spinner Brad Hogg to be caught at backward point.

Yusuf Youhana fell to Michael Kasprowicz?s bowling for 30 after putting on 74 runs with Inzamam. Kasprowicz followed up by trapping Inzamam leg before at 204 for six in the 44th over.

However, the 24-year-old Afridi helped Pakistan plunder 62 runs from their last five overs. Afridi, who holds the world record for the fastest one-day International century with a 37-ball hundred against Sri Lanka in 1996, stunned Lee with a square drive for six in the 46th over.

The right-hander, who has three one-day International centuries to his credit, then struck McGrath (two for 54) for consecutive sixes over cover and mid-wicket in the next over.

Afridi, who also hit four fours, recorded his fourth six when he clubbed Lee (one for 66) over cover in the final over.

In reply, Australia?s makeshift opening combination of Clarke and Simon Katich (38) added 107 after replacing Matthew Hayden and injured wicketkeeper/batsman Adam Gilchrist who were rested for the match.