Barry Nicholson grabbed a double as Aberdeen eased to a victory that leaves Dundee United still at the foot of the Scottish Premier League.
Nicholson had set up the opener, when Derek Stillie could only parry his 25-yard effort and Darren Mackie was on hand to drive the loose ball home.
Midfielder Nicholson added the second from a long-range free-kick.
Barry Robson replied from the penalty spot, but Nicholson restored the lead, heading home Richard Foster's cross.
Defeat piles more pressure on beleaguered United manager Craig Brewster.
And it justified Aberdeen counterpart Jimmy Calderwood's decision to put out an extremely adventurous line-up.
Captain Russell Anderson and Jamie Smith had replaced Zander Diamond and Andrew Considine.
Scott Severin was pushed forward and Smith roamed just behind a front pairing of Mackie and Lee Miller.
But it took them a while to create a chance against a United defence in which fit-again Lee Mair had replaced Stuart Duff.
Stillie comfortably dealt with a Chris Clark drive and dived low to hold a curling effort from Smith.
United offered little in attack until David Proctor forced Jamie Langfield into making a great save in the 37th minute courtesy of a downward header following Robson's cross.
But it was the Dons who made the breakthrough when Nicholson's drive from 25 yards drew a block at full stretch from Stillie.
The ball rolled into the path of Mackie, who slotted home his third goal of the season.
Aberdeen nearly doubled their advantage when Mackie just failed to get a touch on Clark's searing shot.
But they did go further ahead 40 seconds after the break when Nicholson sent a free-kick curling into the top corner from 25 yards.
Scott Severin fired just wide and Stillie blocked well from a Gary Dempsey drive as the Dons came close to extending their lead.
But, when Craig Conway slumped to the ground under pressure from Michael Hart, Robson stepped up to fire low past Langfield from the spot.
Aberdeen restored the advantage two minutes later, when Foster's cross from the left was headed in by Nicholson at the far post.
Substitute Chris Maguire nearly put the icing on the cake for the Dons late on, but his effort was ruled out for offside as a poor United side suffered their third defeat in a row.
Aberdeen: Langfield, Anderson, Severin, Hart, Nicholson, Dempsey, Jamie Smith (Maguire 77), Clark, Foster, Miller, Mackie (Considine 85).
Subs Not Used: Soutar, Winter, Macauley, Donald, Paton.
Booked: Jamie Smith, Anderson, Hart, Clark.
Goals: Mackie 39, Nicholson 47, 71.
Dundee Utd: Stillie, McCracken, Archibald, Mair, Kalvenes (Duff 46), Proctor, Kerr (Conway 57), Cameron, Robson, Hunt (Goodwillie 57), Samuel.
Subs Not Used: McLean, Kenneth, Gardiner, Easton.
Booked: Duff.
Goal: Robson 70 pen.
Att: 10,747
Ref: C Thomson