Rashford has endured an underwhelming season with the Red Devils thus far and has even been linked with a move away when the campaign concludes, with the likes of Barcelona and Arsenal reportedly interested.
Rashford has made 26 appearances for Manchester United this season, scoring five goals and had an altercation with the club's fans following their elimination from the UEFA Champions League by Atletico Madrid recently.
He was overlooked by England manager Gareth Southgate for the ongoing international matches because of poor form.
Rooney is Manchester United's record goalcorer with 253 goals but he believes Rashford can break that record if he is able able to recapture his old form.
Rashford has scored 93 goals for Manchester United since his debut in 2016.
“To get the record and be United’s highest goal scorer is f***ing massive," Rooney said at a black-tie event in Manchester over the weekend - as reported by The Sun.
“What I hope is that Marcus Rashford f*cking gets his head out of his a*se and goes and breaks that record. He is a Manchester lad.”
