Aston Villa boss Tim Sherwood says Jack Grealish needs to work harder to reach his potential.

Grealish had to watch the first half of Tuesday's 1-0 League Cup win over second city rivals Birmingham from the bench - before being unleashed to turn the game.

Sherwood said: "He did well, especially when he gets the space.

"I had a word with him in the week about trying to put some work-rate in out of possession.

"I'm not asking him to be a tiger, but I want him to get himself into a shape - it might be easier, when we win the ball back, for people to find him.

"I think he's willing to learn because he's got the potential to be a top player. He's a developing player."