Hendrie netted his first Championship goal for the Blades with twenty-one minutes remaining to continue an unbeaten run in the year 2008.
Since the multimillion buy out of the London club the Loftus Road based club have seen their fortunes wavered as they rocked themselves off the bottom of the table after spending £5,000,000 on eight new players.
Akos Buzsaky who is one of the eight new stars nearly found a way through for the visitors early on in the game - his low strike was saved by Paddy kenny.
And the £500,000 signing from Plymouth Argyle was once again foiled by Kenny who somehow pared his dangerous free-kick over the bar at point blank before the home side woke up and came back in abundance.
Lee Camp, the Hoops keeper pulled off two brilliant saves, David Carney saw his effort pushed round the post before Rob Hulse's tinkering cross was palmed round the post.
But, just before half-time the away side went ahead after a misfortunes error from Leigh Bromby, a Matthew Connolly cross in the box slipped off the former Sheffield Wednesday defenders feet as Agyemang pounced and fired into the roof of the net, 0-1.
Billy Sharp, who had already seen his effort hit the back of the net but ruled out for offside looked to have levelled for the Blades when he charged through and chipped over Camp - but Fitz Hall hooked away with Rob Hulse unable to steer home from close range.
After the break the home side were on level terms but in a fashion and needed some luck, in 64th minute Michael Tonge hit a long range strike which was saved by Camp, but Martin Rowlands in an attempt to clear hit against Damion Stewart and could only watch as the ball spun over the line to the delight of the Bramall Lane faithful., 1-1.
And four minutes later all three points were heading in the direction of Sheffield United when lee Hendrie grabbed his first league goal for the Blades since he made his free transfer from Aston Villa last July.
He, and Connolly challenged for Billy Sharp's cross with the Rangers man handballing in the box - referee Mr. Miller was on the verge of reaching for his whistle when Hendrie plucked himself up before slamming the ball home to a jubilant 28,000 crowed.
The game looked won, but the visitors hadn't given up the ghost just yet with Rowlands being denied a certain goal, the Blades failed to clear the area and the former Brentford midfielder struck a half-volley which was headed off the line by Matthew Kilgallon with the visitors claiming handball.
The result lifted the Blades in fourteenth spot and seven points ahead of next weeks opponents Sheffield Wednesday who, as a result of their 1-0 defeat at Cardiff City occupy one place above the drop zone.