Aston Villa kept up their challenge for fourth place in the Premier League with a win at relegation-placed Reading.
Young's goal set Villa on their way to victory
Villa's Gareth Barry missed a dubiously-awarded penalty before the visitors went ahead when Ashley Young slotted home after a counter-attack.
Nicky Shorey had a shot parried as the Royals fought back, but Marlon Harewood curled in a shot to secure Villa's win.
Reading efforts did receive their reward in injury-time when Shorey scored with a 25-yard free-kick.
But the loss was their eighth on the trot and the foundations for it were set early on.
The home side's defence had looked uncertain at the start and it was a sign of things to come as they gave the home fans plenty of cause for concern.
Any promise that James Harper's early shot, which stung the hands of Scot Carson, had briefly given the Royals quickly evaporated by a shaky back-line.
Centre-back pairing Kalifa Cisse and Ibrahima Sonko failed to clear a high Villa ball and John Carew seized on the loose ball to screw a shot just wide.
Young was given space to run at the home defence and his shot was saved before Gabriel Agbonlahor's pace saw him break clear down Villa's left flank.
He put in a low cross for Carew but Cisse blocked before the danger was before quelled with some desperate defending.
Reading were given little respite, and Harper petulantly nudged Villa boss O'Neill when the ball went out for a throw-in near the visitors' technical area.
Villa boss O'Neill (left) and Harper exchanged words on the touchline
Barry was given the chance to exact a swift revenge for his manager when the referee awarded a harsh penalty for a Cisse handball from Shaun Maloney's shot.
The normally precise England midfielder sliced a poor spot-kick wide but it did not stop Villa momentum.
Martin Laursen had a header saved by Royals keeper Marcus Hahnemann before the inevitable goal for Villa came just before half-time.
Agbonlahor burst clear on the right before squaring the ball across for Young, who controlled and sidefooted in.
Reading exerted a spell of decent pressure in the second half and almost levelled when Shorey's angled shot was only parried by Carson.
A mix-up between the keeper and his defenders nearly let in Stephen Hunt but the visitors eventually cleared the danger.
Carson blocked a looping Shorey free-kick, which appeared to get a faint touch by Dave Kitson, as Reading pegged the visitors back.
But another swift Villa break as Reading pushed forward ended with Harewood curling an effort into the far corner to secure his side's victory.
Shorey scored with virtually the last kick of the game when his set-piece squeezed past Carson as he notched a Reading consolation and their first goal since 12 January.
Reading boss Steve Coppell:
"They had the edge in many areas, we fought well but just need more quality, we need to get better.
"When you're down at the bottom you clutch at things that can give you a little boost, to change your form.
"Hopefully Nicky Shorey's consolation goal can do that as we need something against the clubs that are with us in the mini-league at the bottom now.
"The penalty was an absolute nonsense and I thought it was poetic justice that Barry missed the kick."
Aston Villa boss Martin O'Neill:
"We looked a threat all day, scored some great goals and played openly.
"Until we got the second goal it was difficult to breathe easily as we had to pick ourselves up after missing the penalty, but we scored at vital times.
"The second goal sealed the win for us, so we're still in there battling, still competing to finish fourth.
"Barry doesn't miss too many from the spot, but he apologised at half-time where there is no need, as he's pulled us out of a hole more than a few times in the past."
Reading: Hahnemann, Murty, Cisse (Ingimarsson 71), Sonko, Shorey, Oster (Kebe 58), Harper, Matejovsky, Hunt, Doyle (Long 71), Kitson.
Subs Not Used: Federici, Bikey.
Booked: Sonko, Matejovsky.
Goals: Shorey 90.
Aston Villa: Carson, Gardner, Laursen, Davies, Bouma, Young, Reo-Coker (Osbourne 86), Barry, Maloney (Harewood 73), Carew, Agbonlahor.
Subs Not Used: Taylor, Knight, Salifou.
Goals: Young 45, Harewood 83.
Ref: Martin Atkinson (W Yorkshire).
BBC Sport Player Rater man of the match: Aston Villa's Ashley Young 8.17 (on 90 minutes).
Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.