Denly fought hard for 12 -- the top score of the innings so far.
Leeds: England captain Joe Root fell for his second successive duck as his side slumped to 54-6 at lunch on the second day of the third Test at Headingley on Friday.
Fast bowler Jofra Archer had taken a Test best 6-45 as England, looking to level the five-match series at 1-1, dismissed Ashes-holders Australia for 179 on Thursday's opening day after Root won the toss in overcast conditions.
But even though the blue and sunny skies above Headingley ought to have made life easier for the hosts' batsmen, there was always the chance England's fallible top-order would be undone by Australia's quicks.
Josh Hazlewood duly proved that theory correct by taking 3-26 in 11 overs, with England six down in 24.
World Cup-winning opener Jason Roy, new to Test cricket this season, took guard having made just 40 runs in four innings this series.
He fell for nine in familiar fashion on Friday when he edged a drive off Hazlewood to David Warner, holding the first off four catches at first slip.
Roy's exit saw Root come into warm applause on his Yorkshire home ground. But Root, arguably England's best batsman, was out for a second ball nought when he was undone by a straighter Hazlewood delivery that seamed away a touch, with Warner doing the rest. Hazlewood had taken two wickets for no runs in three balls, with England 10-2.
- Careless Stokes -
It was Root's second straight nought after he was out for a golden duck in the second innings of the drawn second Test at Lord's. England were almost 10-3 when new batsman Joe Denly was given out lbw to Hazlewood on nought by umpire Joel Wilson.
But Denly reviewed and with replays showing the ball would have gone well over the top of the stumps West Indian official Wilson, who had a record-equalling eight overturned decisions in a Test in the series opener at Edgbaston, had to reverse his original verdict.
England, however, were 20-3 when Rory Burns was caught behind for nine by Australia captain and wicket-keeper Tim Paine after the left-handed opener's gloved hook off a Pat Cummins bouncer.
All-rounder Ben Stokes came into this match following an unbeaten 115 in the second innings at Lord's. But he all but gave his wicket away when he flat-footedly carved at a wide half-volley from recalled fast bowler James Pattinson he could barely reach, with Warner holding a fast edge high above his shoulder.
Stokes was out for eight and England were 34-4. Denly fought hard for 12 -- the top score of the innings so far. But having done so, his 49-ball stay ended when he was caught behind following an inexplicably extravagant drive off Pattinson.
And 45-5 became 45-6 when Jonny Bairstow, like Root playing at his Yorkshire home ground, was drawn into edging a good-length Hazlewood ball with Warner holding another excellent catch.
There were ironic cheers from a capacity crowd when Jos Buttler got off the mark with a four through the covers off Pattinson that brought up England's fifty.