Andy King scored a last-gasp winner as Leicester City progressed through to the fourth round of the League Cup with a 2-1 extra-time win over West Ham.

Hammers goalkeeper Adrian, who was sent-off in Leicester's Premier League victory at Upton Park last month, was on top form throughout, pulling off a string of superb saves to deny Claudio Ranieri's men.

The hosts raced into an early lead courtesy of Joe Dodoo's first goal at the King Power Stadium, only for Mauro Zarate to restore parity for Slaven Bilic's side in the 26th minute.

But despite the excellence of Adrian, Leicester sealed the victory late in extra-time – King rising highest to head home powerfully from Christian Fuchs' cross.

Leicester made the perfect start as Dodoo, who netted a hat-trick in the second-round win over Bury, drilled a low finish past Adrian – who had previously done well to deny Leonardo Ulloa – six minutes in.

Dodoo would have had another soon after if not for a timely James Collins block, before Andrej Kramaric squandered a gilt-edged chance to extend Leicester's lead.

They were made to pay for the miss when Zarate picked up possession on the edge of the area and his strike deflected in off Marcin Wasilewski.

Making his first start since January, Andy Carroll was almost gifted a goal when Mark Schwarzer parried Aaron Cresswell's free-kick in his direction, but the veteran goalkeeper recovered well.

Adrian displayed his quality after the interval – parrying Marc Albrighton's fizzing drive wide before tipping Ulloa's header over.

The Spanish stopper was then equal to Fuchs' free-kick, and again had to be alert to deny King from latching onto a superb pass from substitute Riyad Mahrez.

And though Jeffrey Schlupp and Mahrez both wasted golden opportunities in the first half of extra-time, King was on hand to head in the winner with four minutes remaining.