Harry Kane's late penalty earned an FA Cup third-round replay for Tottenham after a 2-2 draw against Leicester at White Hart Lane on Sunday.
Christian Eriksen put Spurs ahead after just eight minutes before Marcin Wasilewski's powerful header against the run of play levelled the scores 11 minutes later.
The Foxes went ahead thanks to substitute Shinji Okazaki's fine run and finish just after the break and looked set to hold on until Kane's late intervention.
The visitors had frustrated Spurs for large periods, but the Tottenham forward slammed home his 50th goal for the club to secure a replay after Nathan Dyer was penalised for handball.
The two sides play again in the Premier League on Wednesday, and ahead of that repeat encounter, both managers made several changes. Claudio Ranieri handed a debut to new signing Demarai Gray while Mauricio Pochettino rested Kane and Dele Alli.
One of those to keep their place, though, was Eriksen, and the midfielder fired Spurs in front to capitalise on early pressure from the hosts.
Josh Onomah found Chadli in the inside left channel, and the winger's deflected effort was parried clear by Kasper Schmeichel, only for the ball to land at the feet of Eriksen, who guided a low shot back past the Leicester goalkeeper.
The visitors were not behind for long as Wasilewski quickly got them back on level terms. The defender had been booked just prior for a lunge on Danny Rose, but escaped the marking of Toby Alderweireld from Gray's corner to power a header past Michel Vorm.
The Foxes, happy to sit back and soak up Tottenham's pressure, often put 11 players behind the ball, and it successfully handcuffed the home side for the reminder of the first half.
Gray looked dangerous on the break and teed up Ben Chilwell on the half-hour mark, but the full-back's cross was gathered by Vorm with Ulloa unmarked at the far post.
Dier tested Schmeichel with a dipping shot from distance, but Tottenham rarely threatened to add to Eriksen's early strike before the break.
And the away side made them pay just two minutes after the restart as Okazaki poked the Foxes in front. He slalomed his way past Alderweireld and saw his initial effort come back off Vorm before forcing it home at the second time of asking.
Pochettino brought on Alli, Nabil Bentaleb and Kane in response as Spurs pushed for an equaliser, but they struggled to carve out clear-cut opportunities despite enjoying 73 per cent possession.
Alli summed up the frustration when he clattered the excellent Chilwell, before the England midfielder went close with an improvised header from Alderweireld's long ball.
Gray, who looked lively on his debut, nearly put the game beyond Spurs but his stinging shot from range deflected just wide of Vorm's far post.
Okazaki then headed wide from a Marc Albrighton cross as Leicester continued to ask questions on the counter, but the final stages saw sustained Tottenham pressure.
Schmeichel acrobatically kept out Bentaleb's swerving shot from just outside the penalty area, before a strong run from the impressive Rose earned the 88th minute penalty. The Foxes were furious and Schmeichel was booked by Bobby Madley for his protests after Rose's cut-back popped up onto Dyer's hand, but the referee had no hesitation pointing to the spot.
The Leicester 'keeper gathered his composure, but could do little to stop Kane's spot-kick, which was dispatched high and hard past Schmeichel even though the Foxes stopper dived the right way.