Chelsea capitalised on Ander Herrera's sending-off to win a hard-fought FA Cup quarter-final with holders Manchester United and maintain their pursuit of a domestic double.
Herrera's dismissal for two fouls on Eden Hazard gave the advantage to the Blues midway through the first half.
The brilliant N'Golo Kante fired home the only goal - his second this season, both of which have been against United.
Chelsea dominated thereafter but spurned chances to add to their lead.
United, who were without forwards Zlatan Ibrahimovic, Wayne Rooney and Anthony Martial, produced just one clear opportunity - Marcus Rashford denied by Thibaut Courtois.
Chelsea join Arsenal, Tottenham and Manchester City in a semi-final line-up featuring four of the top five teams in the Premier League.
Chelsea has been drawn against Tottenham with City has been drawn against Arsenal.