LONDON - Ki Sung-Yueng slotted an extra-time winner past former Socceroos goalkeeper Mark Schwarzer as Sunderland claimed an upset 2-1 win over Chelsea in the English League Cup quarter-finals.
Schwarzer produced a terrific save to prevent Ki's 114th-minute header, but couldn't stop the South Korean five minutes later when he cut inside a pass from Liverpool discard Fabio Borini before drilling a shot into the bottom corner with the 41-year-old Australian going the wrong way.
Gus Poyet's team had been on the verge of defeat at the Stadium of Light after goal-line technology was used for the first time in the League Cup to give Chelsea the lead through Lee Cattermole's own goal in the opening minute of the second half.
Borini equalised for the Premier League's bottom club in the 88th minute before Ki sent Sunderland into the semis.
It was Ki's first goal in 13 appearances for the Black Cats since his loan switch from Swansea, with whom he won the League Cup last season, in September.
Ki had never scored in English football since moving to Swansea from Celtic in 2012, and this was his first club goal since he netted for the Scottish giants at Hibernian in February 2012.
"It was just unbelievable, I didn't expect to score but I am really pleased to help the team go through," Ki told Sky Sports.
It was a dispiriting night for Blues boss Jose Mourinho, who won the League Cup twice in his first spell in charge of the west London club but saw his fears about his shot-shy team confirmed during a lacklustre display.