The ex-Everton hitman had hauled the Sheffield side back into the match in the 57th minute with a header to cancel out Stephen Elliott's first-half strike before he was pulled back by Gary Breen.
The 28-year-old striker, who has rediscovered his scoring touch after a miserable time at Goodison Park, finished clinically, with substitute Jon Stead adding a third in stoppage time.
Wolves tested United in the opening minutes, full-back Kevin Foley pumping over a cross from the right flank which was met by the incoming Stephen Ward but his header flew high and wide of the target.
Danny Webber linked with Michael Tonge as he fired wide of the far post from 16 yards and minutes later the United striker produced another spectacular effort, this time hammering the ball inches over.
The Blades, showing the flair that had been missing so far this season, should have gone ahead on 18 minutes as Stephen Quinn's teasing cross deceived everyone except Matt Kilgallon whose header hit the bar from the tightest of angles as Webber slammed the loose ball wide.
Michael Kightly caught United on the break, his angled drive drifting a fraction wide of the target before Wolves grabbed the lead on 24 minutes.
Kightly threaded the ball to Stephen Ward whose low shot was spilled by Paddy Kenny and Elliott lashed the loose ball into the net.
Elliott should have added a second five minutes later as he ran onto Any Keogh's header but he ballooned his volley over the bar while Keogh pulled the ball wide from 12 yards as United panicked.
The Republic of Ireland international caused problems linking with Kightly as he drilled a shot from 25 yards into the side-netting before United pulled level on 57 minutes.
Full-back Leigh Bromby's long ball into the area was met by Beattie and Wayne Hennessey but the striker got the first touch as the ball trickled over the line.
United escaped in the 76th minute when they failed to clear Kightly's free-kick, skipper Breen headed back at the far post and Darren Ward hit the bar as he steamed into the goalmouth.
Beattie scored his second in the 82nd minute after Breen's moment of madness and Stead finished off the Midlands side with a goal two minutes into stoppage time.