Billy Sharp netted his first hat-trick for the club as an impressive United brushed QPR aside at Bramall Lane in August 2008.
The Blades were too sharp for the visitors as they opened their points tally in the 2008/09 Coca-Cola Championship.
There were a number of fine performances - including Sun Jihai - as United bounced back from the previous week's disappointment at Birmingham City.
Blades: Kenny, Halford (Cotterill 67), Naysmith, Morgan (Ehiogu 34), Kilgallon, Henderson, Sun, Speed, Tonge, Sharp (Webber 83) Quinn.
Unused: Stead, Spring.
QPR: Cerny, Delaney, Hall, Leigertwood, Parejo, Blackstock, Gorkss, Connolly, Cook (Alberti 81), Balanta (Di Carmine 45), Ledesma.
Unused: Camp, Stewart, Mahon.
Attendance: 25,273
Referee: G Laws