Brazilian defender Thiago Silva will leave Chelsea at the end of the season after a "dream" four-year spell at Stamford Bridge.
Chelsea extended the contract of 38-year-old centre-back Thiago Silva to the end of the 2023/2024 season on Friday.
Chelsea aim to put a turbulent past couple of months behind them by winning the Club World Cup final against Palmeiras on Saturday, the start of a season-defining period for the European champions
Ziyech broke the deadlock with his dazzling long-range curler early in the second half at Stamford Bridge.
Pep Guardiola's men are on a daunting run in the Premier League which started with a 1-0 win over Chelsea at Stamford Bridge.
Chelsea manager Thomas Tuchel suffered the first defeat of his reign as struggling West Bromwich Albion took advantage of Thiago Silva's red card to earn a stunning 5-2 win on Saturday.
Chelsea's three of the new signings, Ben Chilwell, Thiago Silva and Timo Werner were on the scoresheet on Saturday, while another Hakim Ziyech won man-of--the-match for two assists.
Frank Lampard said he enjoyed coaching a player with so much "intensity in wanting to perform at the highest level" even in the twilight of his career at age 36.
Frank Lampard's side dominated from start to finish thanks to an influential display from Hakim Ziyech.
Chelsea were 3-0 down in the first half, but came back strong to salvage a point thanks to goals from Mason Mount, Callum Hudson-Odoi and Tammy Abraham.