Chelsea boss Antonio Conte says his side must increase their efforts to stay at the top of the pile going into the new Premier League season.
The Italian ended any speculation over his future by signing an improved two-year deal on Tuesday although the length of his contract has not changed as he was already tied down until 2019.
Chelsea won the Premier League with relative ease last season, finishing seven points clear of closest rivals Tottenham, but Conte says they must improve if they are to successfully defend the title.
Chelsea are 4.33 to win the Premier League next season and Spurs are available at 9.00, with Manchester City rated as the 2.88 favourites.
“I am very happy to have signed a new contract,” said Conte.
“We worked extremely hard in our first year to achieve something amazing, which I am very proud of. Now we must work even harder to stay at the top.”
Chelsea have been fairly busy in the summer transfer window as they seek to strengthen their squad ahead of another tilt at the Premier League crown.
Antonio Rudiger and Tiemoue Bakayoko have arrived from Roma and Monaco respectively while keeper Willy Caballero has joined as a free agent.
However, Conte is still seeking to bolster his striking options, with Diego Costa expected to move on although so far he has been left frustrated.
A move for former forward Romelu Lukaku failed after the Belgian opted for Manchester United while Borussia Dortmund have stressed Pierre-Emerick Aubameyang will not be leaving the German club following links with the Blues.