The on-loan Manchester United winger scored for the Black Cats' Under-23s in their 2-2 draw with Tottenham earlier this week to underline he is now fully over his recent ankle injury, which kept him out for six weeks.
The 21-year-old was a late substitute in last weekend's 2-0 defeat at Liverpool but now he wants a starting role ahead of Saturday's home clash with champions Leicester City.
"I started for the Under-23s earlier this week which was good to help my fitness," he said. "It's good to be playing games again after being out and it will help me find my levels.
"It was a good goal and it helped the team and hopefully it will lead to me scoring first-team goals as my ambition is to score in the Premier League, so hopefully I can get my chance and take it this weekend.
"It was good to play but I felt like I was getting into my rhythm at Sunderland so [the injury] did come at a bad time, but I'm getting back now and I'll be on top of my game very soon."
Januzaj is hoping the busy festive period will offer him plenty of opportunities to impress David Moyes, as he added on the club's website: "There are lots of games over Christmas and every player is needed so we will all get a lot of playing time, and that’s very important for me.
"We have some big games coming up but they are games we can take points from. My job is to score goals and create them so hopefully a lot of that."