Under-fire Sheffield United boss Bryan Robson conjured arguably one of the sweetest results of his career as the Blades took a second Premier League scalp in this season's FA Cup, beating Manchester City 2-1.
Former Manchester United captain Robson saw his side clinch a place in the fifth round after holding onto a first-half lead courtesy of goals from Luton Shelton and Jon Stead.
Rising teenage star Daniel Sturridge gave City hope with a stunning volley three minutes after his arrival as a half-time substitute, but United were barely troubled beyond that.
For Robson, the victory will have come as a major relief as there had been rumours this week his job was on the line following last weekend's 2-0 derby defeat at Sheffield Wednesday.
But even Robson must have chuckled to himself at the comical nature of his side's first goal inside 12 minutes.
A swift break down the left wing resulted in Lee Martin - on loan from Manchester United - delivering a low cross into the area where a myriad of blue balloons were floating around the area courtesy of the 6,000 City fans behind Hart's goal.
Michael Ball was clearly confused as he completely missed his attempt at a clearance and Shelton pounced to slot home.
An infuriated Hart then proceeded to stamp on and burst all the remaining balloons in his area, as well as the majority behind his goal.
City were also similarly fired up as they had three chances for an equaliser prior to Stead doubling United's lead in the 24th minute.
Initially, a fit-again Emile Mpenza planted a free header over the crossbar from eight yards.
Then Elano struck the left-hand post with a right-foot shot from 20 yards, and followed up shortly after with a curling free-kick that kicked up off the turf, only for Paddy Kenny to pull off a sensational one-handed save.
Effectively, against the run of play, the Blades made it 2-0 to the unbridled joy of Robson on the touchline.
This time the goal stemmed from the right wing and a cross from Derek Geary the City defence struggled to clear, with the loose ball falling for Stead to drive home from 12 yards.
United managed to see out the remainder of the half without too much threat from their opponents, only to be caught out by a slice of magic from City's up-and-coming striker Sturridge.
The 18-year-old replaced Elano at half-time and was in the right place to take a ball that had skimmed off the head of a falling Dunne from a Vedran Corluka corner.
Showing the composure of a veteran, he then knocked the ball up with his right knee before volleying home from 15 yards with his left foot, but the City comeback never eventuated and they were bundled out.