Pakistan's record 45-run triumph locks in a return match in the tri-series final, but Australia will have to lift significantly for that clash in Harare on Sunday.

After Finch's fireworks powered Australia to big victories in their first two games in Zimbabwe, the Victorian opener was dismissed for only 16.

Finch smashed his own T20I record on Tuesday against Zimbabwe by belting 172, which went with an unbeaten 68 a day earlier.

But as soon as Finch departed, Australia's hopes of winning their third straight game and overtaking Pakistan at the top of the T20I world rankings went with him.

Pakistan powered to 7-194 - their highest T20I score against Australia - after being sent into bat by Finch at Harare Sports Club on Thursday.

It was a completely different game to the one the teams contested on Monday when Australia brought up an easy nine-wicket win.

"I don't think we got going all day. We were a long way off with the ball and in the field," Finch said.

"I thought it was around a 170 (run) wicket but we let them get away a bit and our fielding was really sloppy as well and a disappointing day all round."

The other Australian batsmen were unable to get going and pick up Finch's slack as fellow opener D'Arcy Short struggled to 28 from 34 balls.

Former Test batsman Nic Maddinson, who is without a state contract and hadn't played a T20I since 2014 before this series, finally got a chance to bat.

But after coming in at No.5, Maddinson had a scratchy stay at the crease before being stumped for five.

Wicketkeeper Alex Carey looked the most likely of Australia's batsmen with an unbeaten 37 and could be set for a stint up the order after batting at No.7.

Pakistan's innings was built on a fast start and finish, but stagnated in the middle overs after Hussain Talat was dismissed for 30 when Pakistan were 1-80 in the ninth over.

Pakistan's innings slowed up even more after opener Fakhar Zaman fell for 73 to Marcus Stoinis five overs before the end.

But some clean hitting from Asif Ali (37 not out) ensured Pakistan posted a score that proved too much for Australia.

Andrew Tye and Jhye Richardson picked up two wickets each, but all Australian bowlers went at close to 10 runs an over.

Australian Associated Press