The 24-year-old is irritated by this criticism and feels he deserves more respect for his goal scoring achievements.
“Year in, year out people expect 20 goals from me,” Lukaku told reporters.
“I’ve been doing it for 10 years straight so I think I’ve proved myself.
“You expect a bit more respect, but it’s the situation we’re in. I don’t listen to it. I just want to improve and show the people what I can do on the pitch.”
Lukaku has 13 goals in 27 Premier League games for United and feels his critics are ignoring his record.
“That’s the situation around me,” he said, adding “I just need to keep working hard. I think I’ve got a nice record.
“I’ve scored a lot this season and I just want to keep going. I know that I can improve and I want to improve and really work hard.”
