The 22-year-old, who joined Chelsea from Wigan Athletic last summer, has made 40 appearances for the Blues this season, scoring 10 goals in the process.
"I wasn't expecting to play as many games as I have this season but I feel I've worked hard on the training ground and done well," he told the club's official website. "Because of the amount of games we've played, especially having joined the Europa League as well, that's definitely helped me play more.
"At this stage of the season there's not any time to even think about tiredness; you just need to focus on getting yourself in the right shape for the next game. Every match is important for us at the moment and we need to make sure we keep winning in order to finish in the top three, which is our aim."
"We want to be playing Champions League football next season and we've also got the Europa League final to come so, if we can win that as well, it will be a fantastic end to the season."
Chelsea host fellow Champions League hopefuls Tottenham Hotspur in the Premier League on Wednesday.