Chelsea received a double setback ahead of Sunday's showdown with Manchester United as Thibaut Courtois was forced to withdraw from their squad, while Marcos Alonso pulled out during the pre-match warm-up at Old Trafford.
Belgium goalkeeper Courtois suffered an ankle injury in training and was replaced in goal by Asmir Begovic.
It was Begovic's first Premier League start of the season.
There was more bad news for Blues boss Antonio Conte just minutes before kick-off as left wing-back Alonso, who reportedly felt unwell earlier in the day, withdrew from the team after initially joining the rest of the squad on the pitch.
Alonso was replaced in the starting line-up by Kurt Zouma.
United manager Jose Mourinho, whose side face Anderlecht in the second leg of their Europa League quarter-final on Thursday, made four changes, with Zlatan Ibrahimovic among those dropping out.
David de Gea, Ander Herrera, Marouane Fellaini and Ashley Young came in, with Sergio Romero, Michael Carrick, Henrikh Mkhitaryan and top scorer Ibrahimovic making way. Young was named captain.
"He's tired, very tired," Mourinho said of Ibrahimovic.
"I'll try to protect him, but let's see the result. He's on the bench and ready to help."
Leaders Chelsea are bidding to restore their seven-point advantage over second-place Tottenham Hotspur, who cut the gap to four points by beating Bournemouth 4-0 on Saturday.
Sixth-place United are seeking to move closer to the Champions League places.