Lauren James was the name on everyone's lips after her solo goal lit up Chelsea's 3-2 victory over Tottenham - earning the player-of-the-match award as her team went top of the Women's Super League.
"She's fantastic but she's got to learn some other things like the last parts of the game - getting back into position," the Blues boss told BBC Two.
"That's for me to deal with with her. On the ball, she's outstanding but we need to be patient. She needs to keep developing both sides [of her game]."
James' opening goal was a spectacular solo effort. She used her skill to part the home defence, gliding in from the right flank before coolly tucking the ball past keeper Tinja-Riikka Korpela with a finish described as "perfect" by former Spurs captain Jenna Schillaci.
"Lauren James' goal was phenomenal," said Schillaci. "When James gets the ball at her feet, she is able to just glide past players.
"She's so difficult to play against. I played against her a few times - you can't get near her. It doesn't look like she's running that fast but it's the strength and the way she moves her body.
"She's a phenomenal talent."
James joined Chelsea last season in a hotly anticipated move from Manchester United but she arrived with injury problems which plagued her campaign.
She made only six league appearances, accumulating just 116 minutes.
But this season has been a marked improvement for the 21-year-old and she has already featured in 10 WSL games, scoring four goals.
On Sunday she proved a constant menace to Spurs, with her four touches in their box the most of any player.
"Lauren James is a young player and she is developing. When she is on the ball, she gets us off our seats and she gets at players," said former England midfielder Fara Williams.
"As a coach you want her to do both sides of the game and she will learn that and develop that the more she plays in this Chelsea team. But the games I have seen as of late, the consistency she has shown has been brilliant."
James is a product of Chelsea's academy but had spells with Arsenal and United before returning in 2021.
She made her first senior England appearance against Austria in September's World Cup qualifier, and has now played five times for her country after being rewarded for her resurgence at club level.
"I'm happy," James told BBC Sport after the win over Spurs. "You always play your best football when you're happy. Coming back in at the start, it was difficult finding momentum - but with the team around me, it's allowed me to grow.
"I'm loving it. Credit to Emma and the team. They've allowed me to be myself and grow gradually, they haven't forced anything. They've allowed me to be at my best."
But with Hayes insisting there is more James can do to improve her game, is tough love what the England player needs?
"It works sometimes," says Williams. "Some players like an arm round them and being told they are the best player in the world. Other players need to be kept on their toes to give a little more. Maybe Lauren is that player.
"Emma will know better than anyone else what Lauren James needs to get the best out of her."
Schillaci agrees Hayes is the right person to get the best out of the forward.
"Emma Hayes is more like the mum figure, she is never happy and always wants more," she said.
"No doubt that will come; she has brought the best out in her so far."