First Test, Lords (day two, close):
Australia 253 & 100-4 v Pakistan 148
Watson's maiden five-wicket haul put Australia in a strong position on day two
By Oliver Brett
BBC Sport at Lord's
Shane Watson proved to be the surprise danger man with the ball as Pakistan were bowled out for 148 in reply to Australia's 253 in the Lord's Test.
Watson took a career-best 5-40 with key strikes in each of his first three overs to give Australia a big advantage in what had been an even contest.
And by stumps on day two, the Aussies had stretched their lead to 205 as they reached 100-4 in their second innings.
Though Ricky Ponting fell for nought, the dogged Simon Katich was 49 not out.
Despite three interruptions for rain or bad light, the match developed quickly from its overnight position, with Australia resuming at 229-9 when play started on Wednesday.
Mike Hussey added 17 to his unbeaten 39 before Mohammad Aamer (4-72) bowled last man Doug Bollinger with a full and fast delivery.
But Pakistan, who managed to lose a Test in Sydney at the start of the year despite bowling out the Aussies for 127, were always likely to face a harsh batting examination with the cloud cover remaining thick, and thus making for friendly conditions for the seam bowlers.
One batsman prospered, the left-handed opener Salman Butt, who made 63 in a two-and-three-quarter hours. He left alone wisely but also hit 12 boundaries, often in his favoured arc either side of point.
The rest of the Pakistani batsmen were less adept at dealing with the swing on offer as the innings lasted one ball shy of 41 overs.
Ben Hilfenhaus made the first two incisions with deliveries that shaped away from the outside edges of Imran Farhat and Azhar Ali just enough to elicit thin nicks to wicketkeeper Tim Paine.
The second of those left Pakistan 49-2 at lunch, and that became 54-3 when Umar Amin was surprised by extra pace from Mitchell Johnson, giving Paine a third comfortable catch.
It was still possible for Pakistan to have designs on some sort of lead when Umar Akmal, their best batsman, strode to the wicket to join Butt.
But Watson angled one into his pads with the batsman expecting him to swing it down the hill, dismissing him leg before wicket. Akmal had barely unstrapped his pads when brother Kamran fell in identical fashion.
Butt was the ninth Pakistan wicket to fall as the Australia bowlers dominated
The responsibility of captaincy has not restrained Shahid Afridi, who responded to the growing crisis with one of the most indiscrete innings witnessed at Lord's.
In 15 minutes he faced 15 balls, crashing four fours and two crowd-pleasing sixes, but Watson held his nerve, sent down a slower inswinger and Afridi holed out to mid-off.
Bollinger, who had disappointed with the new ball, steamed in from the Pavilion End to remove two tail-enders, and Watson finally breached Butt's defences with a peach of a delivery that swung between bat and pad.
Pakistan were nine down at tea, and, after a quick drink, Watson returned to take his fifth wicket, making him the first bowler to appear on the new neutral honours boards at Lord's.
The final session was a long one, as time was made up for various stoppages, and Australia's openers Katich and Watson made good headway to put on 61 for the first wicket.
But Mohammad Asif and Umar Gul each took two wickets to give Pakistan's fans some encouragement.
Asif had Watson edging a drive, before Ponting completely misjudged a ball in the bowler's next over which swung down the hill and into his pads as he played no shot, though umpire Rudi Koertzen also played his part in the dismissal, the ball having swung so much it would have missed leg stump.
Gul then picked up the baton, bowling Michael Clarke and removing Hussey for a first-ball duck as his edge just carried to first slip.
But Katich, who had hit 80 on Tuesday, again accumulated patiently square of the wicket to form the bedrock of Australia's batting and add to the growing feeling that he has become his team's most reliable batsman.