Match ends, Leicester City 1, West Ham United 1.
Wilfred Ndidi scored a 90th-minute equaliser to break West Ham's resolve after they looked set to take all three points despite Mark Noble's first-half sending-off.
Centre-back Fabian Balbuena had put the visitors in the lead, reacting first to the rebound from his own header, to prod home after 30 minutes.
Just eight minutes later Noble was shown a straight red card for a high, lunging tackle on Wilfred Ndidi.
West Ham frustrated Leicester, while Lukasz Fabianski made some crucial second-half saves.
Jamie Vardy had dominated the pre-match discussion, with reports the former England striker was angry at being dropped for the game.
The 31-year-old, who was forced off against Arsenal on Monday with a stomach bug, started the game on the bench and Leicester manager Claude Puel said the player was not "100% fit", despite Vardy declaring himself so via Instagram on Friday.
As it was, Vardy came on at half-time and offered more of an attacking threat. He went close with a header and late in the game had a fierce strike saved by Fabianski.
With the Hammers poised to take all three points, Ndidi's long-range shot took a wicked deflection off Balbuena to beat Fabianski.
There was concern at the end of the game, as Leicester right-back Daniel Amartey left the pitch on a stretcher in injury-time in some pain with an injury to his ankle.
More to follow.
Match ends, Leicester City 1, West Ham United 1.
Second Half ends, Leicester City 1, West Ham United 1.
Attempt blocked. Marc Albrighton (Leicester City) left footed shot from the centre of the box is blocked.
Attempt saved. Shinji Okazaki (Leicester City) header from the centre of the box is saved in the centre of the goal. Assisted by Ben Chilwell.
Daniel Amartey went off injured after Leicester City had used all subs.
Delay over. They are ready to continue.
Delay in match Daniel Amartey (Leicester City) because of an injury.
Attempt missed. Angelo Ogbonna (West Ham United) left footed shot from the centre of the box is high and wide to the left. Assisted by Robert Snodgrass.
Goal! Leicester City 1, West Ham United 1. Wilfred Ndidi (Leicester City) right footed shot from outside the box to the top left corner. Assisted by Demarai Gray.
Attempt saved. Jamie Vardy (Leicester City) right footed shot from the centre of the box is saved in the centre of the goal.
Offside, Leicester City. Ben Chilwell tries a through ball, but Shinji Okazaki is caught offside.
Attempt saved. Michail Antonio (West Ham United) right footed shot from the centre of the box is saved in the bottom right corner.
Pablo Zabaleta (West Ham United) is shown the yellow card for a bad foul.
Offside, Leicester City. Marc Albrighton tries a through ball, but Jamie Vardy is caught offside.
Corner, Leicester City. Conceded by Aaron Cresswell.
Offside, Leicester City. Demarai Gray tries a through ball, but Shinji Okazaki is caught offside.
Attempt missed. Angelo Ogbonna (West Ham United) header from the centre of the box misses to the right. Assisted by Robert Snodgrass with a cross following a set piece situation.
Substitution, West Ham United. Angelo Ogbonna replaces Felipe Anderson.
Substitution, Leicester City. Shinji Okazaki replaces Caglar Söyüncü.
Foul by Caglar Söyüncü (Leicester City).
Michail Antonio (West Ham United) wins a free kick on the left wing.
Attempt blocked. James Maddison (Leicester City) left footed shot from the right side of the box is blocked. Assisted by Daniel Amartey.
Offside, Leicester City. Marc Albrighton tries a through ball, but Daniel Amartey is caught offside.
Substitution, West Ham United. Aaron Cresswell replaces Grady Diangana.
Attempt missed. Daniel Amartey (Leicester City) right footed shot from outside the box is too high. Assisted by Harry Maguire.
Foul by Harry Maguire (Leicester City).
Pablo Zabaleta (West Ham United) wins a free kick in the defensive half.
Corner, Leicester City. Conceded by Pablo Zabaleta.
Foul by Wilfred Ndidi (Leicester City).
Michail Antonio (West Ham United) wins a free kick on the left wing.
Harry Maguire (Leicester City) hits the bar with a header from the centre of the box. Assisted by James Maddison with a cross following a corner.
Corner, Leicester City. Conceded by Robert Snodgrass.
Attempt missed. Wilfred Ndidi (Leicester City) left footed shot from outside the box misses to the right.
Dangerous play by Vicente Iborra (Leicester City).
Declan Rice (West Ham United) wins a free kick in the attacking half.
Attempt missed. James Maddison (Leicester City) left footed shot from outside the box is high and wide to the left. Assisted by Wilfred Ndidi.
Attempt missed. Jamie Vardy (Leicester City) header from very close range is just a bit too high. Assisted by Marc Albrighton with a cross.
Attempt saved. Marc Albrighton (Leicester City) left footed shot from the right side of the box is saved in the bottom right corner.
Attempt saved. Marc Albrighton (Leicester City) right footed shot from the right side of the box is saved in the centre of the goal. Assisted by Ben Chilwell.
Hand ball by Michail Antonio (West Ham United).