A huge chance missed for the hosts as they could have moved into fourth place.
Burton held on for all three points.
Story of the game
After the touching two minutes silence before the game in honour of The Duke of Edinburgh, Prince Phillip, the game got underway.
The home side got off to a bright start, and won a corner which was taking by Ronan Curtis, and Sean Clare of Burton did well to clear.
The Brewers did well to respond to early pressure and the first real chance of the game fell to Mike Fondop. The Cameroonian's header was saved well by Craig MacGillivray in the Pompey net.
Unfortunately for the hosts, Lee Brown had to come off injured after just 25 minutes, he was replaced by former Bournemouth defender Charlie Daniels.
The visitors came close again this time with Hayden Carter, with his first Burton goal last week the on-loan Blackburn Rovers defender has certainly got an eye for goal. Another good save by MacGillivray.
The biggest chance of the first half for the hosts fell to Tom Naylor, he fired a shot just wide after a clever corner-kick routine.
On the stroke of half time, Fondop gave the visitors the lead. Another dangerous Tom Hamer throw-in was met by Carter, his volley was well saved. The ball bounced around the Pompey box and eventually Fondop slashed the ball into the top corner, great goal.
Just a minute after the break the visitors double their lead, this time it was Joe Powell. The 22-year-old with a 35 yard screamer. No chance for any goalkeeper in the world.
Just a few minutes later Danny Cowley made a double substitution, in a bid for his side to make some kind of comeback.
Yet again, the long throws were causing Pompey problems. This time John Brayford couldn't find the back of the net, and it's a let off for the hosts.
Portsmouth started to apply slight pressure to the visitors, they had a glorious chance to pull one back. However, once again, he couldn't keep it down.
Late on Lucas Akins nearly made it three for the away side, but his one on one chance was saved well by the Portsmouth 'keeper
To add even more pressure late on, substitute Daniels scored to pull one back for the hosts, the defender headed home his first goal for Pompey.
Finishing 2-1 to Burton, it was a great game of football at Fratton Park. Ending in a huge win for Burton.
Changes for Brewers come up trumps
After goalscorers Fondop and Powell came into the squad over top scorer Kane Hemmings and Jonny Smith, they knew they had to impress.
With both of them scoring the decisive goals, they did exactly what Haselbaink would have wanted.
They both came off after around the 70th minute, but it was a good run-out for the boys.
Huge chance missed for Pompey
With results around them kind of going their way, its a huge chance missed for the home side.
Facing this Burton side was never going to be easy, however the recent upturn in form for both sides could have sent the game in either direction.
A disappointing loss, where they could have scored multiple times but bad finishing was the pinnacle of their problems.
Joe Powell - Burton Albion
After scoring a screamer, and overall playing a great game coming in for Jonny Smith.
It would be rude not to give the MOTM to him.