Arsenal needed extra time and penalties to beat second division Sheffield United, England defender Ashley Cole converting the decisive spot-kick to win the shootout 4-2 following a goalless draw.

Striker Peter Crouch scored twice to help Southampton beat third division Brentford 3-1, and Blackburn's Morten Gamst Pedersen lashed in an 86th-minute winner to seal a 2-1 victory over local rivals Burnley.

Southampton will entertain holders Manchester United in the last eight, Arsenal travel to Bolton Wanderers and Blackburn host second division Leicester City.

Second division Nottingham Forest play Tottenham Hotspur in the last fifth-round replay on Wednesday with the winners travelling to Newcastle United in the quarter-finals on March 12 or 13.