Chelsea boss Maurizio Sarri believes in-form Marcos Alonso can still improve on the defensive side of his game.
The left-back is one of seven players to have been nominated for August's Premier League Player of the Month award, having claimed a goal and an assist in his side's opening three wins of the season.
Alonso has also earned a recall to the Spain squad, having been overlooked for the World Cup this year.
Sarri, nominated for the Manager of the Month prize, is happy with Alonso's form but insists he can still sharpen up when the opposition have the ball.