It was the teenager's Premier League debuts, with Elanga also making his first ever senior appearance.
"The young players who played tonight did an amazing job and showed that the club can count on them in the future," Matic told MUTV.
"They showed that they will be very important for our club in the future. They played with personality, they showed the character, so I was very happy to see them on the pitch. The way they played was great, against a very good side in Leicester, it's not easy to play.
"I remember when I was young, that I always watched the older players to see how they behave, how they play, how they train. I always try to be an example for the young players. I hope that I can help them."