The Portuguese midfielder has had a striking impact at Old Trafford since his transfer in January.
Fernandes has yet to taste defeat in a United jersey and has played a crucial role in much of his team's undefeated run.
His introduction came at a very necessary time, especially in the absence of the injured Rashford, who was impressed by Fernandes' qualities from the sidelines.
Speaking in a live question and answer session on Instagram, Rashford told Bleacher Report: "He is a creative player, very forward thinking. He always wants to play forward and create opportunities.
"I hope we can have a good time together.
"He has such a positive attitude and the atmosphere he brings to the team is just positive.
"Even if he loses the ball, he works to come back and it definitely rubs off on the other players. "
Fernandes has been particularly productive on the field of business, scoring three goals and providing four assists in nine appearances in all competitions.
The first of his goals for United came in a 3-0 victory over Watford, where Hornets defender Craig Cathcart was unfortunate enough to be on the opposing side.
"I think we were all impressed," said Cathcart.
"What impressed me most was that he was always looking forward. He always gets the ball and his first thought is to step forward and create chances, which maybe [United] were missing before.
"He brought that little bit of avant-garde quality to the last third and since he came in, their performance has been much better, from what I've seen. "
Fernandes is already hailed as a future great United, with club legend Paul Scholes one of the last to comment on the 25-year-old.
"He gave life to a lifeless attacking team," Scholes told BT Sport. "He made a team that was not at all observable sometimes very observable.
"His creativity, his awareness on the field ... before the ball comes, he knows what's going on. Most often, it makes the right pass. It is sensational.
"You look at your [Eric] Cantonas, your Wayne Rooneys, these people who are idolized by the fans, you hope that in the future he can become a player as good as they are.
"Sometimes it may take a player to make a team click and he looks like that player. "