Jose Mourinho has urged Anthony Martial to follow midfielder Henrikh Mkhitaryan's example and force his way into Manchester United's starting line up.

Martial has found himself on the fringes of Mourinho's first-team plans, having made four of his 11 Premier League appearances from the bench this season, but the manager said he had no plans to sell the 21-year-old French striker.

"Anthony is very, very young -- people forget -- and last season Manchester United played completely differently. He was basically playing up front," Mourinho told British media.

"The team had lots of passive ball possession, just waiting to put it into space for Anthony to go and score a goal. This season is more difficult. He needs a little bit of time to improve."

Armenian Mkhitaryan also struggled to get into the side in the early part of the season but made his breakthrough with a fine display in the Europa League against Zorya Luhansk earlier this month.

"Every player is different. I had this season a situation that was more difficult than Anthony -- Mkhitaryan," Mourinho added.

"Mkhitaryan was completely open and understood the difference between me and other coaches he had.

"The difference between the demands of the Premier League and the Ukrainian league, or even Bundesliga: complete different philosophy of play. And he worked a lot without playing, but he worked a lot to try to reach the level."

United, who are sixth in the league, 13 points behind leaders Chelsea after 18 games, host 15th-placed Middlesbrough on Saturday.