Chelsea suffered their first Women's Super League (WSL) defeat under Sonia Bompastor, ending a 34-game unbeaten streak, after they lost 1-0 to Everton on Sunday.
It is the first time Chelsea have lost in the league since May 2024, when Liverpool defeated the reigning champions 4-3 while under the helm of former manager Emma Hayes.
It is also the first defeat for Bompastor in the WSL since joining last summer. She ended her debut season with a record points tally, collecting 19 wins and three draws.
"[It was a] really frustrating result for sure," she said after the game. "We are really disappointed, but if you analyse the game, we knew Everton was coming, and we needed to be really switched on in transitions.
"The performance was not a bad performance from us, but today we couldn't score, and we couldn't win the game. In terms of performance, I think we were dominant. But again, in football, the most important is to win."
Honoka Hayashi struck in the 12th minute to take an early lead for the Toffees, who had picked up only one win -- the open day victory over Liverpool -- heading into the afternoon, and Chelsea struggled to reply, despite creating significant opportunities.
Chelsea generated 30 chances -- six on target, nine blocked, and three rattling the woodwork.
Despite delivering 53 crosses, the Blues were repeatedly denied by Everton's resolute defending, as the visitors produced 87 clearances to bring a historic unbeaten run to a bruising halt.
It was the first time in 31-straight league games that Chelsea failed to score. The reigning champions, who have claimed the last six titles, are now six points behind Manchester City following the loss and three draws against Manchester United, Arsenal and Liverpool.
City have not dropped points since the opening day defeat to Chelsea.
The loss also mounts pressure on Chelsea's Champions League campaign. The Blues are sitting in sixth, outside of the top four who earn automatic qualification to the knockouts, but only one point separates them from Bayern Munich in third place.
Failure to end the phase in the top four will enter them into the playoffs in February, a week after they face Manchester City in the league, which could be a title-deciding game.
Chelsea face Roma in the Champions League on Wednesday before their final league game of 2025 against Brighton.
They play Wolfsburg away to round out their continental league phase before facing Liverpool in the quarter final of the League Cup -- they are also holders of the title -- to complete the calendar year.