Hazard has re-discoverd his form of two years ago when his performances for Chelsea helped the club win the Premier League and the League Cup trophy - and earn the Belgium international the PFA Player of the Year award too.
Januzaj has spent the past two seasons out on loan at Borussia Dortmund and, this term, at Sunderland where he has set up three goals in 20 appearances.
The 22-year-old admits having to move from club to club hasn't been easy, but says he is drawing experience from Hazard to try and improve his game each week.
Speaking to the Sunderland Echo, Januzaj said: "I can learn from him. He has more experience than me.
"When you are playing against Chelsea there are more players who can make a difference so it’s harder to track all of them.
"I watch a lot of games in the Premier League when I have free time and that’s where I learn.
"He [Hazard] is a good friend to me. He is a top player. Whenever he has the ball he is dangerous.
"He is one of the best players in the Premier League, if not the best, he has so much talent now and I know him well."
Januzaj added of his time this season with Sunderland, who sit rock bottom in the Premier League table: "It has been very difficult because it is not easy to go from Man United to Sunderland.
"I had to just do it, I will learn from it because I am 22. People think I am 26 or 27, I am only 22. I know people want more from me.
"I have learned a lot here and it will make me stronger."