Steve Smith has swung the second Test in Australia's favour with his evening heroics on day one, says Andrew Strauss.
England had recovered from slipping to 28-3 in the morning session at Lord's to reach 271-4 after tea, thanks in large part to Ian Bell (109) accruing a third century in as many Ashes Tests.
But part-time leg-spinner Smith rocked the hosts by taking the scalps of Bell, Jonny Bairstow (67) and Matt Prior (6) in an eye-catching six-over spell (3-18) to leave Alastair Cook's men sat on 289-7 at stumps.
Former England skipper Strauss called Michael Clarke's decision to bring the 24-year-old into the attack a "masterstroke", and says Smith's exploits have put Australia, who lost the first Test at Lord's by 15-runs, in the ascendancy.
"Smith has changed the game completely and wrestled it from England's favour," Strauss told Sky Sports Ashes HD.
"He was almost thrown the ball out of desperation by Clarke as he was struggling for ideas, but it was a masterstroke.
"Perhaps England weren't expecting Smith to bowl and that's what did for them, but he produced a beauty to get rid of Bell and while Bairstow's ball was a full toss, a really good quicker one got rid of Prior."
Ryan Harris, meanwhile, recalled to the Australia side in place of left-arm quick Mitchell Starc, seized the wickets of Joe Root (6), Kevin Pietersen (2) and Jonathan Trott (58).
And Strauss's fellow pundit, Nasser Hussain, says he was not surprised to see the burly paceman, who has been blighted by injury in recent years, create havoc having witnessed him training during last week's gripping first Test in Nottingham.
"We watched Harris bowl in the nets at Trent Bridge and he looked a phenomenal bowler," said the ex-England skipper.
"He has had problems with injury and not played too much cricket and sometimes with players like that they lose rhythm and a bit of nip.
"Harris has not, though, and he is a very good line bowler who pitches the ball up."
Bell led England's charge with the bat and not only followed on from his 109 in the opening Ashes encounter by notching another ton, but also joined the list of players to score 1,000 Test runs at Lord's.
And Strauss - who scored 1,562 runs in his 18 Tests at headquarters, placing him second on the all-time list behind current England batting coach Graham Gooch (2,015 runs in 21 matches) - was full of praise for the Warwickshire stroke-maker.
The former Middlesex man also applauded half-centurion Bairstow - who was handed a reprieve when he was castled off a no-ball from Peter Siddle - but believes England underachieved as a batting unit in north-west London on a relatively smooth track.
Strauss added: "Bell was very fluent all day and when he plays like that he makes batting look easy.
"He showed a lot of touch, scored in different areas, and is making the most of his form which is always the challenge for a batsman.
"Bairstow, a good boundary hitter, played well - he got a bit of luck early on, but he made use of that luck and played some good shots - though he will be frustrated he got out as he would have been thinking about getting a hundred.
"But England haven't had a great day; they may have settled for 289-7 at 28-3 but when you bat first at Lord's, especially on a wicket like this which looked very flat at times, they would have wanted two fewer wickets lost."