Thomas Tuchel has become the first Chelsea manager to keep clean sheets in his opening three matches for 17 years.
Since replacing Frank Lampard last week, Tuchel has guided the Blues to seven points from games against Wolverhampton Wanderers, Burnley and Tottenham Hotspur.
Chelsea have barely conceded a chance in any of those fixtures, a vast improvement on the club's defensive record during the final weeks of Lampard's reign.
With the shutout against the club's London rivals on Thursday night, Tuchel matched the record set by Mourinho at the start of his first Chelsea spell.
Mourinho watched his side record shutouts against Manchester United, Birmingham City and Crystal Palace in August 2004 before conceding in the first minute of his fourth match.
Chelsea have moved up to sixth position in the Premier League standings as a result of their recent haul under Tuchel.