Chelsea set up an FA Cup fifth-round tie against Leeds United thanks to a convincing 3-1 victory over Aston Villa.
Gallagher was teed up by Madueke for an 11th-minute opener and Jackson, who was also involved in that goal, added a second not long after for the visitors via a header.
Villa created next to nothing and found themselves three down nine minutes into the second half at Villa Park through a sublime Fernandez free-kick into the top-left corner.
Diaby did pull one back for Emery’s side, but it was far too late to mean anything as Chelsea returned to winning ways.
Villa will switch focus back to the Premier League on Sunday with a home match against Manchester United, while Chelsea will face London rivals Crystal Palace at Selhurst Park next Monday.
