Chelsea subbed off a defender at 12 minutes and their scorer at halftime, then beat City

Chelsea beat Manchester City 1-0 at Stamford Bridge on Saturday, ending the champions' unbeaten start and moving one point above them at the top of the Women's Super League. Sonia Bompastor got there after taking off a center back in the 12th minute, losing a forward to injury in the 35th and replacing her goal scorer at halftime.

Khadija Shaw got the better of Kadeisha Buchanan in City's first two chances, and Bompastor didn't wait. She said Buchanan took a knock to the head in training on Friday and was cleared that night and again on Saturday morning, but she didn't look right from the begining of the game.

"I just felt watching her from the beginning of the game, she was not herself. Then I took the responsibility to make the substitution," Bompastor told reporters, according to ESPN. "It hasn't happened many times to me in my experience. I think you have to be brave to make that decision in that moment."

Veerle Buurman, who had dealt well with Shaw in last season's FA Cup semifinal, came on and was named player of the match. Then Melvine Malard pulled up with a hamstring injury and Aggie Beever-Jones replaced her.

Sandy Baltimore scored in the fourth minute of first-half stoppage time, turning on Ellie Carpenter's pass on the right side of the box and firing over Ayaka Yamashita. At halftime, Bompastor took her off for Maika Hamano.

She explained it was about the clock, not the performance. With one substitution window left and Baltimore unlikely to last past 60 minutes, using it then would have left Chelsea with half an hour and no changes available. "It paid off," she said.

City pushed hard after the break and should have equalized in the 64th minute, when Shaw flicked the ball over Hannah Hampton and Lauren Hemp missed it from about a yard out. Carpenter then wasted a free shot at the back post at the other end.

The game turned in the 75th minute. Yamashita ran well outside her area for a ball over the top, Alyssa Thompson got there first and knocked it past her, and the City goalkeeper brought her down. The referee showed a straight red, and Yamashita will serve a one-match ban. Eartha Cumings came on in goal, and Beever-Jones hit the crossbar with the free kick.

"To have a player sent off, it was difficult to swing that momentum in our direction," City defender Jade Rose told BBC Sport.

Chelsea have 26 points from 10 games, one more than City, who started the day two points clear. They've conceded five league goals all season.

Chelsea visit Paris Saint-Germain in the Champions League on Wednesday. "We're in a better place than we were last year," Keira Walsh told the BBC. For Bompastor, the bigger takeaway might be that a day of three forced changes, including one most coaches wouldn't dare make, ended with her team on top.