Christian Pulisic can give "a lot more" to Chelsea than he has in his Stamford Bridge career to date, according to head coach Frank Lampard.
The United States international did not make a start in the Premier League for almost two months before an explosive performance against Burnley in October saw him score a hat-trick in a 4-2 win.
Further strikes against Watford, Ajax and Valencia followed, but Pulisic has not now registered a goal or an assist in his past four appearances.
Although Lampard has been pleased with his development, he will not let up in the demands he places on the £58million winger.
"I have just mentioned there about conversion of chances. I think he gets himself in so many good positions with his talent and his dribbling ability that I think more goals will be the next stage of that," Lampard told reporters ahead of Chelsea's meeting with Bournemouth on Saturday.
"I am really pleased with him. I have asked a lot of him. He has played a lot of games recently, back to back, in a new league that we know is very physical for him. I am asking a lot, but he has done very well. I expect a lot more."
Fikayo Tomori is one youngster to have impressed consistently for Chelsea this season, and the centre-back was rewarded with a new five-year contract on Thursday.
"He has come a long way, and that is all his own work," Lampard said. "From the moment he came to Derby County [on loan last season], he has shown a work ethic, a want and desire to listen and improve himself.
"His personality has come out even more. He was quite quiet when he first came to Derby; he is less quiet now.
"I think everybody saw his performances in the Championship last year, [he was] Derby Player of the Year. Then [there were] big question marks in the summer over whether he can do it in the Premier League.
"He certainly hasn't proved that yet over a period of time, which is the important thing. But from my point of view, I have full trust in him. I am delighted in him to where he has got to now.
"The important thing now is that he doesn't take anything for granted now that he has got that five-year contract. It is important that the hard work starts again. I am delighted with what he has done."
Lampard is similarly pleased with the progress of full-back Reece James, who has shown signs of real promise when deputising for Cesar Azpilicueta.
"I don't want to compare him to anyone. I just want to concentrate on Reece himself," Lampard said. "He's got a great role model in Azpilicueta, who has been doing it for years here in terms of how he's been playing in recent games.
"His attitude – talk about urgency and intention to get up and down the pitch and give everything and set the tone – I think it's great for Reece to see that as well alongside him every day. But Reece also brings a real quality in his delivery and in his forward play.
"There's work to do with him, he knows that, he's a young player. So, I think he's done really well on his first steps into the team. Again, like some of the other young lads, I expect a lot more from him because I can see the quality in him."