His late winner against Aston Villa was credited with turning around a losing run and giving them the much-needed impetus to seize their then record-equalling 18th title.
That was back in 2009, and its fair to say that three-and-a-half years on that goal remains his career highlight, he has barely got close since.
United signed Michael Owen the following summer, which limited his first team opportunities, and Macheda struggled to make an impact in the opportunities he was afforded.
Last season he scored just one goal, a penalty in the club's League Cup defeat to Crystal Palace, and he would at least have hoped for another run out in this year's competition.
No such luck. The Italian was included in the 22-man provisional squad for the game against Newcastle, but failed to make the starting 11, or be named among the seven substitutes.
It was a real blow, and emphasises that he is further away from the first team than ever before. Even at this stage last year with Dimitar Berbatov, Michael Owen and Mame Diouf all competing for spots, he started away to Leeds, and it has been a backwards step for him.
There are mitigating factors, had it not been for Wayne Rooney's injury earlier in the season, and the need to give him game time last night, Macheda would likely have featured in some capacity, even if only on the bench.
Secondly the draw against Newcastle demanded Sir Alex Ferguson play a strong side, especially with Alan Pardew's confirmation ahead of the match he would be playing first team stars Cheik Tiote and Fabricio Coloccini.
But last night's fourth round draw, away to Chelsea, offers little solace for Macheda, who faces being left on the sidelines again with United likely to play another strong side.
With Robin van Persie's arrival, strikers Danny Welbeck and Javier Hernandez are losing out on game time, and have only been playing more frequently recently than they otherwise would because of Rooney's injury.
The competition is great news for the club, but Macheda is the odd man out. The 21-year-old still has plenty to offer, but he is not getting a chance to show it.
He has been on two loan spells, which were fruitless, with Sampdoria and QPR, and Sir Alex Ferguson admits his worry over whether they were counter-productive held him back sending youngsters including Macheda out on loan this year.
The Italian has been doing what he can, he scored the club's first goal on their pre-season tour of South Africa, he netted a brace for the under-21s against Tottenham recently too, but clearly it hasn't been enough to force his way into the first team reckoning or even the bench of a League Cup squad.
He has four options - (a) leave now on loan for a Championship club until January (b) wait until January and try for a loan move to a Premier League club (c) try to secure a permanent deal, or (d) wait around for an opportunity which might never arrive.
The difficulty with a loan to a Premier League side, is this - Ask yourselves which clubs Macheda would walk into the starting line-up at?
Even newly promoted Reading and Southampton with Pogrebnyak and Rickie Lambert would likely see him sitting on the sidelines, and Macheda has not played any top flight football since January 2012, briefly at QPR.
A season long loan would have made sense, if it were agreed in August, and Macheda must be very frustrated right now that the most realistic oportunity of first team action so far this season has passed him by.
What is Macheda's best option? What should he do?
image: © apasciuto