Eden Hazard says a lack of motivation was behind Chelsea's dire Premier League title defence last season and admits the squad will be "in trouble" next term should they let standards slip.
Under Antonio Conte, the Blues recovered from a disappointing 10th-place finish under Jose Mourinho and Guus Hiddink to take the title back off Leicester City, who mounted an even worse title defence.
Chelsea's form tailed off so badly that the defending champions briefly flirted with relegation and Hazard hinted that hinted "motivation" and "fitness" may have played a part in the club's slump.
He told BBC's 'Football Focus': "That's football. Sometimes you are on the top, two years ago we won also the league, but last season was difficult for some reasons.
"Sometimes motivation is not on the top, fitness is not on the top, so a lot of things.
"(This season) we started well and we won the league, but next season we will be in trouble if we don't work hard like we did this season.
"We need to be ready every year in the same level to be on the top."
Chelsea secured this season's Premier League crown with a 1-0 victory over West Brom on May 12 after leading the table for much of the season.
Major celebrations have had to be put on hold, however, with the Blues set to take on Arsenal in the FA Cup final on May 27.
Hazard has returned to his best form under Conte, scoring 15 Premier League goals this campaign, and is determined to finish a fantastic season in style.
"We can't celebrate a lot because we have the FA Cup final, we have to be ready for that, but after West Brom we did a little party together," Hazard said.
"Even in the dressing room, it was good to see the smile on faces. I think at the end of the season we deserved to win this title.
"It's not just me, the whole team, all the players they have been fantastic. We won a lot of games.
"We have one more game (against Sunderland on Sunday) and the FA Cup final to play. I hope we can win the double."
