Rain washed out the last 22.4 overs of day four as Pakistan fought for survival at a perilous 4-103 after being set 438 for an improbable victory.

After Katich (100) broke his 90s curse to set up an attacking declaration at 5-219, opening partner Watson showed his all-round value by starring in a vital nine-over spell which reaped 2-24.

The 28-year-old ended any faint hopes of a Pakistan miracle in dismissing captain Mohammad Yousuf (23) and Umar Akmal (15), both of whom unsuccessfully referred leg before decisions.

The crucial double breakthrough at 4-83 had Australia closing in for a quick kill before Khurram Manzoor and Shoaib Malik dug in and the showers set in.

Only Hobart’s changeable weather, which is forecast to rain on the last day, appears to be in Australia’s way of a series clean sweep and a record 12th straight Test win over Pakistan.

Ricky Ponting set the tourists an unlikely record run-chase, earlier than expected off a maximum 147 overs, after Australia lost three wickets in three overs after lunch.

Ponting, who enjoyed a 191-run stand with Katich, himself missed out on a second century for the match when he was caught down the leg-side off Malik for 89.

In hindsight, it was fortunate for Australia he was forced to bring the declaration forward.

Any worries of an overly generous declaration on a good batting wicket diminished when Pakistan lost openers Imran Farhat and Salman Butt in the first 10 overs to fall to 2-29.

Farhat edged Peter Siddle behind to give the Victorian his third wicket of the match while first-innings century-maker Butt had his off-stump knocked over by Doug Bollinger.

Katich, with Test scores of 92, 99 and 98 this summer, stroked 13 boundaries to make his fine hundred from 137 balls.

Brief scores: