Hakim Ziyech sent Chelsea into the FA Cup final for the fourth time in five seasons by securing a 1-0 victory over Manchester City, which lost Kevin De Bruyne to injury.
Manchester City will take on Chelsea in the semi-finals of the FA Cup next month, while Leicester takes on Southampton.
Southampton booked its place in the FA Cup semi-finals after a 3-0 win over second tier Bournemouth on Sunday (AEDT) thanks to a brace from Nathan Redmond.
West Ham United crushed third-tier Doncaster Rovers 4-0 in their FA Cup clash, despite multiple changes from Hammers boss David Moyes.
Holder Arsenal was dumped out of the FA Cup as the unlucky Gabriel Magalhaes settled a scrappy clash at Southampton with an own goal.
Wolverhampton Wanderers scraped into the FA Cup fifth round as Vitinha's sublime strike sealed a hard-fought 1-0 win against non-League Chorley on Saturday (AEDT).
FA Cup: Leicester v Southampton