Liverpool U18 boss Gerrard warned: "We've got wonderful footballers in the first team, especially in the attacking positions, so it's not easy.
"It's getting more and more difficult. These kids have to be world class now."
He is due to return to Liverpool's Kirkby academy on Thursday to work with Neil Critchley's under-23 team and former England captain Gerrard added: "The message for Rhian is: 'Well done. You've been superb and deserve all the plaudits you get. How do you improve now?'
"I think if he's got any dreams and aspirations of playing higher than that level then he needs to play at a consistent level and score goals heavily. That's how first-team managers take note."