Leicester underlined their involvement in the Premier League title race with a 2-0 win at hapless Tottenham.
Jose Mourinho's men were seen as the main challengers to Liverpool after a promising start to the season, but they were second best in a limp display in north London.
Jamie Vardy's penalty and a Toby Alderweireld own goal saw Brendan Rodgers get one over his former mentor and send his side second in the table.
Although Spurs made it much easier for them than it should have been, the victory over a team close to them in the table sends a strong message.
For Spurs this defeat follows on from the one at Anfield in midweek, while the manner of it backs up Mourinho's opinion that they were never title contenders in the first place.
Leicester were marginally the better team in the early exchanges but struggled to create anything meaningful, while it took Spurs a good 35 minutes to find any sort of rhythm.
When they did they created two good chances, but Harry Kane uncharacteristically wasted them. The first was from a corner, which he headed over from six yards, and then another header was cleared off the line.
The afternoon turned in first-half injury time when Spurs imploded.
Serge Aurier gave away a penalty, needlessly barging over Wesley Fofana, which referee Craig Pawson had to see again on the pitchside monitor before Vardy drilled home from the spot - his 11th goal of the season.
Mourinho responded by bringing Gareth Bale on, but it had little effect and Leicester thought they had doubled the lead early in the second period.
James Maddison looked to have beaten the offside trap as he burst through on goal from Marc Albrighton's long ball and fired past Hugo Lloris, only for VAR's perpendicular lines to rule he was marginally offside.
There was no reprieve for Spurs, though, as they fell 2-0 behind just before the hour in a manner that summed up their afternoon.
Moussa Sissoko was unaware that Vardy was lurking behind him and allowed the striker to head a cross back across goal and it diverted off Alderweireld into the net.
Son Heung-min had a chance to give Spurs some hope when a corner fell to him at the far post, but he scuffed his shot and allowed Kasper Schmeichel to make a fine save.
From then on it was just a question of whether Leicester were going to pile on the misery on the break.
Vardy had a shot blocked and then another well saved by Lloris, before Youri Tielemans skied an effort over when the Foxes had men spare.