The 18-year-old, who scored two goals on his first start for the Old Trafford club, remains committed to the Premier League champions despite the delay in signing a new contract
The 18-year-old midfielder burst onto the scene with two goals in the victory over Sunderland on October 5 but there have been doubts over his long-term Old Trafford future, with his contract set to expire at the end of the season.
Senior United figures were readying a lucrative salary package fearing that they could lose Januzaj, but, despite having not yet put pen to paper on a new deal, the Belgian-born starlet is adamant he is committed to the club.
"I am happy at Manchester United and I want to commit myself 100 per cent in every game to do my best," he told Kosovo-based television station KTV.
"I want to help Manchester United win the Premier League and become the best player in the world."
All the talk following Januzaj's match-winning performance against Sunderland has been focused on his international future, with the youngster eligible to play for England, as well as Albania, Serbia and Turkey although he insists it is his dad who will make the final call.
"It is my dad who decides which national team I will play for so I will listen to him," he concluded.
Januzaj is again expected to start for Manchester United in Saturday's home fixture with Southampton.