Rashford was utilised on the wing for most of the campaign and had taken Zlatan Ibrahimovic’s place up front as the club’s top goal scorer had been ruled out with a serious knee injury.
While Anthony Martial had struggled to cement his place in the side throughout the 2016/17 season as a result of poor form which left him the bottom of the pecking order at Old Trafford.
Speaking about the pair, Robson believes they should both be performing better next season.
“They need to be just a little bit more clinical with their goalscoring,” he said.
“The young lads – especially Rashford and Martial – will improve because they’ll be another year older with more experience.
“For Marcus, he’s scored loads of goals at every level he has gone into. When he first came in he was brilliant. But young lads do that. They have a bit of a dip. He has done well but he can do better.
“As Mourinho said, when he scored the goal at Celta Vigo, he’d been out on the training ground practising and practising.
“We know Marcus is there but now we want him to go to the next step. His and Anthony’s aim should be to get over 20 goals next season.
“If they do that, it takes the pressure off other people. Especially if Zlatan [Ibrahimovic] is OK and does stay.
“It also takes the pressure away from the likes of [Henrikh] Mkhitaryan, [Juan] Mata and all of the midfield players.
“Zlatan is the only one who when he gets a chance, puts it away. Juan’s missed a few, Martial and Rashford definitely have. Wayne [Rooney] hasn’t been in great goalscoring form, so what you’ve got to do is improve in that area.
“If they can, those draws will definitely turn into wins.”
Rashford registered 11 goals in the campaign while Martial registered eight and the 2017/18 season will be the third campaign they’ve both will be representing United’s first team.
The future is clearly bright as they’ve both done so well already, but they’re still young and there’s clearly much more progress still to come as they pick up experience.