As expected, Hasselbaink made a few changes in the Emirates FA Cup. In came Flanagan, Palmer and Matthews for Cansdell-Sherriff, Naylor and McLaughlin.
It was a bright start by the Brewers who soon troubled Ben Alnwick in the away goal as Matty Palmer clipped a ball into the box but John Mousinho's flick looped just wide of the left hand post.
The Brewers certainly had the better chances in the first half as Nasser twist and turned past the Posh defence but bent his right footed effort just past the far post.
The away side very nearly caught the Brewers on the attack as a scuffed clearance from Bostwick found Washington who got the better of Palmer down the right hand side before pulling it back to Angol who saw his shot blocked before being cleared by Mousinho.
Another chance went begging for the Brewers as some lovely interchange play between El Khayati, Akins and Duffy provided a great ball across the face of goal but Santos did well to clear the ball away.
Zakuani's second trip to the Pirelli wasn't completed just like the first trip earlier in the season wasn't. This time it was a head injury that forced the centre half off the field, a decision taken by the away physio.
The Brewers very nearly added a goal before half time as a switched ball by Duffy found Binnom-Williams who made a surging run to cut in on his right foot but he was denied really well by Alnwick.
GOAL: On the counter attack, the away side made the breakthrough! A great ball in behind the defence by Smith was met by Washington who fired past Matthews.
HT: Burton Albion 0-1 Peterborough United
The Brewers nearly levelled just two minutes into the second half. A corner taken by Duffy was flicked on by Flanagan which was met by Edwards but Alnwick did very well to tip it over.
On the counter attack again, the Posh troubled theNrewers as Washington ran through on goal with Binnom-Williams chasing but Matthews got there quickest to put off Washington who chipped the ball just wide of the goal. A let off for the Brewers.
Jimmy Floyd Hasselbaink thought a change was needed, or two changes. Beavon and Joachim came on for Akins and Thiele and switched to a 4-4-2.
Matthews made the save of the game, and maybe the season. Taylor lined up a shot from 25 yards which took a huge deflection off Mousinho but the loanee managed to adjust his feet to dive back and tip it over the bar.
The Norwich loanee made another great save as Taylor headed towards goal from a corner but Matthews did very well to get down to his right and deny him.
GOAL: The away side doubled their advantage with 20 minutes to go. A mis-timed header from Edwards made it difficult for Matthews to reach the ball before Washington who raced through and slotted into an empty net.
Duffy had a good chance late on inter game as Duffy received the all with his back to go, he turned but his shot went over.
GOAL: Petereborough added a third late on as Anderson turned home a cross which he really couldn't miss.
Ash's man of the match: Calum Butcher.