Mark Schwarzer has admitted that Chelsea were guilty of not killing Sunderland off following their 2-1 defeat in the League Cup quarter-finals.
The Blues took the lead through Frank Lampard at the Stadium of Light before missing a host of chances to tighten their grip on the game.
They were made to pay when Fabio Borini equalised for Sunderland in the 88th minute, while Ki Sung-Yueng scored the winning goal for the hosts deep into extra time.
"If we got the second goal I think the game would have been killed off pretty quickly but unfortunately we didn't and you leave yourself open to potentially conceding," Schwarzer told the club's official website.
Chelsea are back in Premier League action on Monday when they face leaders Arsenal at the Emirates Stadium.
