Manchester United's perfect start to the Women's Super League season was ended by a pair of goals in four minutes.
United had not conceded a goal in the previous five games.
Sam Kerr fired her shot into the bottom corner past Mary Earps after a sloppy passage of play.
When a long ball got behind the defence and found Kerr in space on the edge of the area, Lauren James was able to convert her simple pass.
In the final moments of the game, United pulled one back, but it was too little, too late.
The top two teams in the WSL are separated by just one point.
Defending champion Chelsea came into this game with five straight wins under their belt and showed their experience against a United team looking for their first ever top three finish.
The first half didn't have many clear-cut opportunities, but they were more comfortable on the ball and kept pegging United back.
The referee didn't see enough for a spot-kick when Maya Le Tissier caught Guro Reiten just inside the area, but it looked like a slip and he didn't appeal.
Earps had to be alert as she saved a looping ball that looked like a cross, and a searching Cuthbert cross made its way to Kerr who volleyed over the bar.
She took her chance when it came and her shot capped off a professional performance where the Blues could have scored more.
Despite the absence of their manager, the defending champions showed their class by executing a professional performance.
United, who have made an impressive start to the season and put themselves in the conversation as title-contenders, have not yet been asked questions about their defence and form against the top sides.
They have put in stellar performances, but this result puts a dent in not only United's perfect start to the season, but their confidence as well.
After a difficult first half, United started the second half much brighter as they tried to get the ball back.
It was clear that the confidence of the United defence had been shattered by the first goal, as they had not conceded a goal in their previous five games.
Kerr was able to finish the move one-on-one with Le Tissier after Ingle passed the ball to him.
The first real test of the season for United was when they conceded again less than a minute later.
But, with a record crowd of 6,186 at Leigh Sports Village, Toone released the player after the ball was thrown away.
The flurry of action gave United a boost as they saw a decent effort from the range sail over and a close one from the other side.
The result showed a huge improvement over last season's 6-1 thumping, but the quality and experience of the team shone through.