In that absurd move, the manager took two of his best players off the field when they needed a goal the most.
But Leicester held on for the draw which leaves Chelsea on 47 points, the same as Manchester United who play on Monday at home to struggling Stoke City.
The Foxes dominated possession for large periods of the encounter and created the better chances than the home team.
Mahrez thought he had should have had a 55th-minute penalty after he tangled with Andreas Christensen, on for the injured Gary Cahill, although referee Mike Jones seemed to have made the right call to turn down the Algerian's appeal.
"In relation to Alexis Sanchez, he is a phenomenal player, apart from that he is an Arsenal player and I feel I shouldn't say much more".
While some may have set up to counter Chelsea at Stamford Bridge, Puel had his side attack the Blues, not giving their players - who had a high-intensity game against Arsenal in midweek - a moment's rest.More news: Trump defends vulgar immigrant comments, partly denies them
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"Then when I made a decision to put fresh energy on, the game changed".
Chelsea then left Wilfred Ndidi completely unmarked at a corner, but the midfielder's header was well saved by goalkeeper Thibaut Courtois.
The hosts were handed a boost when Chilwell was shown a second yellow card for catching Moses, but they found it hard to create openings as Leicester sat back.
"We have to try to improve in this aspect, but the problem is not just for Morata, or [Michy] Batshuayi when he plays".
October 2017: After United beat Benfica in the Champions League, Mourinho aimed a jibe at Conte: "I never speak about injuries".
Abdoulaye Doucoure's controversial last-gasp equaliser denied Southampton a first win in 10 matches.
Antonio Conte's side welcome the Canaries to Stamford Bridge on Wednesday night before travelling to Brighton & Hove Albion in the league next weekend.