ADELAIDE: England's Kevin Pietersen took the key wicket of Michael Clarke with the last ball of the fourth day of the second Ashes test on Monday to reduce Australia to 238-4, still trailing the tourists by 137 runs.

Clarke, who made 80, and Mike Hussey (44 not out) had fought a desperate rearguard action after England declared on 620-5 with a first-innings lead of 375 in the morning.England took three Australian wickets after lunch and the Adelaide rain provided only an hour of respite for the hosts as they looked to the skies to help them avoid an innings defeat.

Pietersen, who had completed his career-best innings of 227 in the morning, was giving the specialist bowlers some rest as the day drew to a close when he made another crucial intervention.

Clarke initially walked when Alastair Cook took the catch but returned to his crease as the decision was reviewed by TV pictures. He was walking again when they clearly showed the ball hit the face of his bat.

England had declared their first innings for the third highest test tally at the Adelaide Oval after nine overs of morning play.

In only 40 minutes, the tourists added 69 runs to their overnight total although the Australians did finally manage to capture the wicket of Pietersen.

The 30-year-old had just posted the fourth-highest test score in Adelaide when left-arm spinner Xavier Doherty finally got some reward for his efforts with Simon Katich taking the catch at slip.

Ian Bell also put on 27 runs -- including a sublime six -- to reach his 25th half century and finish on 68 not out, while Matt Prior made an unbeaten 27 after being saved from an lbw dismissal by a TV review.

Australia openers Katich and Shane Watson had dug in to steer their side safely to lunch but England spinner Graeme Swann struck soon after the break.

Katich, who had hobbled through his innings because of an Achilles heel injury, was the first to go, getting a faint outside edge from a Swann delivery and being caught behind by wicketkeeper Matt Prior.

Australia skipper Ricky Ponting survived 21 minutes and a thorough examination from Swann before getting a thick edge to the 19th ball he faced with Paul Collingwood taking a good catch at first slip.

Ponting reacted with disbelief to his dismissal for nine runs, an improvement on the golden duck he made in the first innings but not the way he wanted to celebrate his 150th test.Watson survived a while longer before being deceived by a quick delivery from Steve Finn and he was also caught in the slips for 57, England skipper Andrew Strauss taking the catch.

Clarke, who seemed out of sorts in his first three innings of the series, finally looked to have found his groove and brought up his half century with a four down to third man.

The 29-year-old, struggling with a long-term back injury before the first test, benefited from the television umpire when he was given caught out on 67 but the review showed the ball had missed his bat.

Rain stopped play for just under an hour and more is forecast for the final day of the test. England are hoping to win an Ashes series in Australia for the first time in 24 years.

Score:

Australia 245 (M. Hussey 93, B. Haddin 56, S.Watson 51; J. Anderson 4-51) and 238-4 (S. Watson 57, M.Clarke 80) v England 620-5d (K. Pietersen 227, A. Cook 148, J.Trott 78, I. Bell 68 not out)