Two outstanding strikes from Sulley Muntari helped Portsmouth to a sixth straight away win against a shell-shocked Aston Villa.
Villa dominated the first half but fell behind early on when scrappy play in their penalty area led to Craig Gardner prodding the ball into his own net.
Muntari's first was a left-footed strike from 25 yards and he then beat two defenders to score with a low shot.
A late penalty for Gareth Barry was little reward for Villa.
Portsmouth had not won in the top-flight at Villa Park for 52 years but they ultimately deserved to end that miserable record if only because of the brilliant goals from Muntari, who produced the two rays of sunshine on a rain-lashed afternoon.
Pompey opened the scoring on 10 minutes after the ball fell to Noe Pamarot wide on the right.
Wilfred Bouma failed to deal with Pamarot's miscued shot and in the confusion Gardner prodded the ball past a stranded Scott Carson and into his own net.
That was harsh on Villa, who pressed hard to get the equaliser, and they were offered two gilt-edged chances to do so.
Both fell to Martin Laursen, who will rue those missed opportunities. In the 18th minute, his free header was saved by David James, and just two minutes later he squandered an even better chance.
Ashley Young's free-kick found him totally unmarked but this time he headed wide from just five yards out. It was almost a carbon copy of his earlier chance - only easier.
Further opportunities fell to Gabriel Agbonlahor and Gareth Barry in a first half Villa controlled.
But they were made to pay the penalty with the first of Muntari's screamers after 40 minutes. The Villa defence failed to close him down as he fired a left-footed shot into the top right-hand corner from 25 yards. It was an unlikely end to the first half.
Muntari's second shortly into the second period was even better. He robbed Nigel Reo-Coker in the Villa half and nutmegged Zat Knight before shooting low into the bottom corner.
Villa didn't deserve to be 3-0 down and they responded well, although they only had a single goal to show for their efforts and that came from the penalty spot.
It was awarded when Distin was adjudged to have brought down Young on the edge of the box with a quite unnecessary challenge and Barry stepped up to reduce the deficit.
Villa continued to seek a way through with Patrick Berger firing over the bar and Olof Mellberg shooting wide.
But as they pressed, Portsmouth threatened to do even worse damage on the break with Papa Bouba Diop guilty of a terrible miss late on.
Aston Villa boss Martin O'Neill:
"Our spirit and determination was there although at times it might have been misdirected but I have no complaints about the attitude of my players.
"This defeat is a body blow because confidence was high but we have to bounce back from this setback."
Portsmouth boss Harry Redknapp:
"Villa Park is not an easy place to come and to score three goals as well as missing other good opportunities was a tremendous performance.
"However, I would think that the top four are on another level to us. They have got the squads and are strong.
"These are great times for Portsmouth, however, 11 games unbeaten. We should make the most of these times."
Aston Villa: Carson, Mellberg, Knight, Laursen, Bouma (Berger 54), Gardner (Harewood 70), Reo-Coker, Barry, Young, Carew, Agbonlahor.
Subs Not Used: Taylor, Davies, Maloney.
Booked: Carew, Berger.
Goals: Barry 72 pen.
Portsmouth: James, Johnson, Campbell, Distin, Pamarot, Utaka (Kanu 64), Diop, Pedro Mendes, Muntari, Kranjcar (Taylor 88), Mwaruwari.
Subs Not Used: Begovic, Hreidarsson, Nugent.
Booked: Pedro Mendes, James, Pamarot, Kranjcar.
Goals: Gardner 10 og, Muntari 40, 61.
Att: 35,790.
Ref: Mike Riley (Yorkshire).
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