A 90th-minute equaliser for Leicester by Craig Hignett dramatically denied Arsenal, who had opened the scoring through Gilberto Silva and had defender Ashley Cole sent off, a valuable victory at the Walkers Stadium.
Chelsea stay a point clear of Arsene Wenger's unbeaten team with 36 points after Damien Duff's second-half equaliser gave them a 1-1 draw at Elland Road.
Champions Manchester United (34) are only a point behind Arsenal after thrashing Aston Villa 4-0 at Old Trafford. Newcastle United and Liverpool drew 1-1 at St James' Park and Wolverhampton Wanderers went bottom after losing 5-2 at Spurs.
Arsenal were without captain Patrick Vieira and striker Thierry Henry for the trip to Leicester.
After a tight first half, Wenger's team, who face a decisive Champions League match against Lokomotiv Moscow on Wednesday, broke the deadlock when Silva, who also later hit the post, headed in a Dennis Bergkamp cross.
Cole was red-carded for a two-footed lunge at Ben Thatcher but Arsenal looked to have held on for a win that would have taken them back to the top until Hignett scrambled in Leicester's leveller in the final seconds.
Chelsea were second best against Leeds in the first half and the home side deserved their lead, secured after 18 minutes when Jermaine Pennant took advantage of a rare Claude Makelele error and beat both John Terry and William Gallas before firing home.
The goal was Pennant's first for the club --- he is on loan from Arsenal --
But Claudio Ranieri's team stepped it up in the second half and equalised when Damien Duff converted a rebound after Adrian Mutu's shot was saved.
Champions United, with manager Alex Ferguson on the bench following a heart scare this week, had their game against Villa won by halftime thanks to Ruud van Nistelrooy.
The Dutchman opened the scoring after a one-two with Kleberson in the 16th minute and grabbed his second with a sharp piece of control and a quick shot on the stroke of halftime.
Uruguayan substitute Diego Forlan then added two more virtuoso efforts in stoppage time to complete the rout.
Improved Fulham stayed fourth on 25 points after two goals in a minute by Sean Davis and Facundo Sava gave them a 2-1 victory over Bolton at Loftus Road.
Robbie Keane scored a fine hat-trick in Tottenham's 5-2 mauling of visiting Wolves, who were beaten 5-1 in north London by Arsenal in the League Cup on Tuesday.
Blackburn also achieved a notable 4-0 victory at Birmingham City. Barry Ferguson, Lucas Neill, Tugay and Paul Gallagher all scored for Rovers in the second half while City had Frenchman Christophe Dugarry red-carded.
Earlier on Saturday Liverpool held Newcastle United to a 1-1 draw at St James' Park. Danny Murphy opened the scoring after six minutes but Alan Shearer earned Newcastle a deserved point from the penalty spot after 62 minutes with his 13th league goal of the season.