A second-half goal from Kai Havertz proved enough to give Chelsea a 1-0 win over Crystal Palace in the English Premier League on Sunday, easing the pressure on manager Graham Potter after a poor run of form.
The German striker nodded in a cross from Hakim Ziyech in the 65th minute following a short corner.
It was only the second league win in 10 matches for the home side who remain in 10th place half-way through the season.
Chelsea were on top for much of the lively if scrappy derby, but Palace kept goalkeeper Kepa Arrizabalaga busy with efforts from Tyrick Mitchell, Michael Olise and Wilfried Zaha.
Kepa was forced into a leaping save from Cheick Doucoure towards the end of the second half.
Midway through the first half, Chelsea announced Ukrainian winger Mykhailo Mudryk had become their fifth signing of the January transfer window.
The 22-year-old waved to fans from the pitch at halftime, a Ukraine flag draped round his shoulders.