Having unluckily been two down at the break, Sir Alex Ferguson's side came from behind through the Portuguese winger to snatch a derby victory that will live long in the memory.
Nani was the last-minute hero for Manchester United as it recovered from a two-goal halftime deficit to defeat Manchester City 3-2 Sunday at Wembley in the most entertaining Community Shield in years.
Nani scored the game-winning goal three minutes into injury time after knocking in the equalizer in the 58th minute. Chris Smalling initially put the Red Devils on the scoreboard shortly after the second half started.
"You see the form of Nani in preseason and today - he will start the season," Ferguson said. "He had a fantastic season last year. He was unfortunate that Valencia came in at a time when we needed a bit of freshness and a boost to the squad."
Manchester City's two first-half goals were scored by Joleon Lescott and Edin Dzeko.
United came out swinging, but City drew first blood. Lescott evaded his marker to meet Silva’s delightful in-swinging free kick to place a precision header into the top corner to get the event started and the Citizens would continue to push forward.
Full of confidence, City sent its neighbors into shock just on the stroke of halftime when a powerful swerving shot from Dzeko flew past David de Gea into the net from some way out, although the young Spanish keeper was late to get down and really should have saved.
Sir Alex Ferguson reacted to entering the half down two by injecting youth into the team, with Phil Jones, Jonny Evans and Tom Cleverley all replacing more experienced heads at the break.
"It just confirms what I thought about the squad,'' Ferguson said. "People were saying that we're not the best United squad and things like that, but you got to remember a lot of these young players have improved."
It seemed to work, with United again starting the half much brighter, and the Red Devils were rewarded quickly when Smalling pulled off a stylish mid-air finish, having been given a worrying amount of space in the City box to reach Ashley Young’s free kick.
And just minutes later, with City in shellshock, a great team move from United saw it draw level. Tom Cleverley, Danny Welbeck and Wayne Rooney were all involved with a devastating series of quick passes on the edge of the box that loosed Nani for a decisive finish, giving the Red Devils their just reward for a barnstorming start to the second period.
United was firmly on top, and with City trying to get forward to re-establish momentum, Ferguson’s side looked dangerous on the counter. Lescott made a great tackle halfway through the second period to rob the ball from an ominously approaching Rooney.
But with the league champion not pressing its advantage home for a winner, City began to recover its confidence. Micah Richards nearly sneaked in a late winner with a powerful header from a far-post corner, but de Gea reacted well to keep it out.
Dzeko and Nani also had late chances saved at either end. But just as it seemed that the game was destined for penalties, a catastrophic error from Vincent Kompany allowed Nani to burst through one-on-one with Hart in the final minute of stoppage time, and he made no mistake, rounding the keeper to slot in a simple, and deserved, winner.
It was a hard-fought contest from the beginning, with the first signs of derby animosity showing after 20 minutes when Dzeko and Anderson clashed over a tackle by the Bosnian forward, each earning a yellow card for their angry reactions.
There were a total of five yellow cards, all of which came in the first half.