Antonio Conte promised Chelsea would do a better job of defending their Premier League title than they did in their last season as reigning champions.
But the Blues got off to the worst possible start when they opened their campaign with a 3-2 defeat to Burnley at Stamford Bridge on Saturday.
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After a Gary Cahill red card within 15 minutes, a Sam Vokes double and a goal from Stephen Ward gave Sean Dyche's team a three-goal lead at the break.
Chelsea fought back to score two goals, but were reduced to nine men when Cesc Fabregas was dismissed and were unable to net an equaliser.
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Their collapse sees them follow in the footsteps of 2015-16 champions Leicester City, who started the following season with defeat to Hull City.
It means that, for the first time in 49 years, the reigning champions of the English top division have lost in the first week in back-to-back seasons.
The last time it happened, Man Utd (1967/68) & Man City (1968/69) were both reigning champions of the league and lost their first game of the following season.