Defending champions Arsenal reached the FA Cup fifth round but were forced to hang on for victory against Brighton at the Amex Stadium.
Theo Walcott gave the Gunners the lead on 89 seconds when he converted Calum Chambers' cross from the right.
Mesut Ozil then made it 2-0 when he slotted in from inside the area.
Tomas Rosicky volleyed home a brilliant third after Brighton's Chris O'Grady had pulled a goal back for his side.
Sam Baldock's goal for the home team set up an exciting final 15 minutes but Arsenal held on to win.
Sunday's other FA Cup results
Aston Villa 2-1 Bournemouth: Carles Gil's stunning goal helped Aston Villa avoid another FA Cup fourth-round giant-killing and see off the challenge of Championship leaders Bournemouth at Villa Park.
Bristol City 0-1 West Ham: Diafra Sakho headed a late winner as West Ham knocked out Bristol City to book their place in the FA Cup fifth round.