After a spirited partnership between Michael Clarke and Usman Khawaja, a flurry of wickets before tea on Sunday has pushed Australia closer to a thumping defeat in the Lord's Test.

Clarke combined with Khawaja for a partnership of 98. Both the captain and the stylish left-hander had posted fighting half-centuries to stop the rot after Australia slumped to 3-36 in the 16th over.

But both fell to the occasional off-spin of England boy wonder Joe Root in the space of three overs.

Then, Steve Smith was caught behind playing an awkward shot to Tim Bresnan. The three wickets fell for two runs in 23 balls to plunge the tourists into desperate trouble at 6-136 at tea.

Khawaja did his best to put the dangerous Graeme Swann out of the attack when he charged into him from behind while completing a run, but had not counted on a bowling cameo from Root, fresh from making 180 to help put the victory target at an unrealistic 583.

Clarke fell to a crafty piece of captaincy from Alastair Cook - caught at leg slip - while Khawaja edged the 22-year-old Root to gully when he had made 54.

The Australian captain was the beneficiary of a missed stumping early in his innings and battled through a barrage of short-pitched bowling from Stuart Broad, who hit him on the shoulder and the helmet in one over. These were the actions of a team determined to ruthlessly drive home the advantage over a weakened opponent.

Australia was set the ambitious task of batting for almost two days on a wearing pitch to save the Test.

The effort to salvage some pride did not start well, and, in Shane Watson's case, amounted to another disappointment.

Watson predictably succumbed lbw for the 10th time in 18 innings against England, this time to Jimmy Anderson for 20, and his opening partner Chris Rogers, spooked by the spin of a previous ball, was bowled by a straight one from Swann.

Phillip Hughes was out lbw to Swann and, for the second time in the match, unsuccessfully challenged the decision, leaving Australia with just one review for the remainder of the innings. That was subsequently burnt by Smith.

Earlier, England declared at 7-339 when Joe Root departed 20 runs short of a double century with a lap shot that was caught at third man. Ryan Harris added two wickets to his first innings haul of five, and has 10 days to rest his injury-prone body before the third Test at Old Trafford.

Watson's innings followed a familiar pattern. He played a sequence of crashing drives, including one chipped in the air that landed just clear of mid-off. Despite his excellent form leading into the series, he has posted scores of 13, 46, 30 and 20 in the two Tests so far.

Rogers, the victim of a bizarre full toss in the first innings, fell to Swann again. The off-spinner got one to kick viciously out of the rough and two balls later Rogers, anticipating spin, shouldered arms and watched the ball crash into his stumps.

Swann, with fielders huddled around the bat and five wickets in the first innings, had 2-10 from seven overs at lunch.