Louis van Gaal has been utilising the Belgium international over the past month in an advanced midfield role behind captain Wayne Rooney.
We just have to utilise his strengths and I think we did that really well on Sunday
Fellaini repaid his manager’s faith with a man-of-the-match performance on Sunday as the Red Devils were 3-0 winners against Tottenham Hotspur.
United winger Young is thrilled to see the 27-year-old turnaround his Old Trafford career after a tough first season at the 20-time English champions.
Young told Sky Sports: “He has been very important for us. He has been in the team and when he is in the box, I’m not sure many teams can handle him.
“You saw against Tottenham that he was fantastic at getting in the box and looking like a striker at times. I think he likes playing in that position. We just have to utilise his strengths and I think we did that really well on Sunday.
“I think last season was difficult for a lot of people and this season is totally different.”
Fellaini was heavily criticised during his first campaign at Old Trafford after the midfielder moved to United in a £27.5m deal from Everton in 2013.
The former Standard Liege man has scored four goals in 18 Premier League appearances this season, including strikes against Stoke City and Queens Park Rangers.
The United midfielder could play a vital role in their clash against Liverpool at Anfield in the Premier League.
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news