It was a special performance that got fans excited and hopeful that the club had unearthed yet another major talent in the game.
For the player himself, it kick-started a promising breakthrough season for the then 18-year-old; Januzaj scored four league goals in 27 appearances in a side struggling for identity in the post-Alex Ferguson era.
His good form, trickiness and eye for the spectacular were rewarded with a bumper five-year deal but things quickly began to change.
United sacked David Moyes — someone Januzaj rates highly as both a coach and person — in 2014 and new manager Louis Van Gaal started using the youngster more sparingly.
Loan spells at Borussia Dortmund and Sunderland did little to boost his reputation at the club, and he eventually was sold to Real Sociedad by then United manager Jose Mourinho in 2017.
“In the past few years, I’ve learned so many things — good things, bad things, everything.
“The good things, I keep doing. My talent will never, never disappear.”
His move to Real Sociedad in Spain’s La Liga has helped Januzaj get his career back on track.
As a pivotal player in the current side, the forward has helped Sociedad to a superb start to the season, with the club currently sitting third having led the league earlier in the year.
He’s also made 13 appearances for the Belgian national team and, thanks to guidance from coaches at his new club, he’s learned to deal better with the mental side of the game.
“When I was not playing a game, I was really nervous and just wanted to play,” he said.
“Even if something goes wrong […] you always have to try and stay stable. For a football player, it’s very important to stay stable in your head.
“It’s been a change in my head, when I’m not playing, I’m calm. If the manager needs me to come on and make the difference, I will come on and make the difference.”
Januzaj says he’s now loving life in Spain and thinks his game is better suited to the more technical style of play.
“Maybe God brought me here,” he said, adding that he has more license to showcase his skills.
He also appreciates the unique position of being a player at Real Sociedad, a club dripping in history and nostalgia.
Until the 1980s, only players from the Basque region could play for the team and, although that policy has since been dropped, the connection with the fans remains as strong as ever.
“You feel that, you can feel the colors, you feel the people, you feel that this is their dream,” Januzaj added about playing in the region.
“If you’re from the team, you feel it because obviously from a young age, that’s the team that you loved.”
Performances again this season have demonstrated just how settled and comfortable Januzaj is at Sociedad, a place which has allowed him to thrive once more.
He may not be the baby-faced trickster he once was — he has just one goal in La Liga so far this season — but he’s matured into a more reliable and consistent performer.
He says things would be different if he were to ever move back to one of Europe’s biggest clubs but insists he is very happy where he currently is.
It’s somewhat of a happy ending for the mercurial youngster who sacrificed a lot at an early age and who, at one point, looked to be sliding into football obscurity.
“When I was 15-years-old, obviously I left my country, went to play in England and I sacrificed a lot,” he said.
“I left everything in Belgium, the school, many things, my parents also, so it’s difficult. That’s a big sacrifice to make.
“At the end of the day, we work very hard and we have to. Sometimes in the morning, you wake up and you feel like, ‘Ahh, I have training,’ but you have to do it.”
At just 26, Januzaj knows he has plenty more to offer in the game, and he’s now finally at a place which gives him the platform to perform.