Antonio Rudiger rescued Chelsea as the German defender's second goal of the game earned a 2-2 draw against top-four rivals Leicester on Saturday.
Rudiger put Chelsea ahead early in the second half at the King Power Stadium before Harvey Barnes and Ben Chilwell scored in quick succession to give Leicester the lead.
A thrilling second half climaxed when Rudiger became the first defender to score a brace for Chelsea in the Premier League since John Terry against Fulham in 2013.
Third-placed Leicester could be more sanguine about the result as they sit eight points clear of fourth-placed Chelsea, who have now won just one of their last five league games.
Frustrated that Chelsea failed to make any signings during the window, Blues boss Frank Lampard claims his team are now underdogs in the race to qualify for next season's Champions League via a top-four finish.
Depending on Manchester United and Tottenham's results, Lampard's prediction could look prescient by the conclusion of the weekend's action.
Showing his irritation with Chelsea's spluttering form, Lampard dropped Kepa Arrizabalaga after some error-prone displays from Chelsea's keeper, with 38-year-old Willy Caballero making his first league appearance since May.
Chelsea started on the front foot and Tammy Abraham appealed for a penalty when he was challenged by Caglar Soyuncu, but referee Lee Mason and then VAR both rejected the claim.
Jamie Vardy was back from injury but Leicester's 17-goal leading scorer hadn't netted in his last four league games and he wasted a good chance to put the hosts ahead when he burst onto Ayoze Perez's chestdown in the penalty area, only to shoot straight at Caballero.
Pedro went close with a clever chip from the edge of the area which Leicester keeper Kasper Schmeichel tipped over at full stretch.
- Sloppy defending -
Leicester were stunned by their late League Cup semi-final defeat against Aston Villa in midweek and they looked low on confidence at times.
Hamza Choudhury should have headed Leicester in front on the stroke of half-time but, befitting their scrappy showing, the midfielder couldn't keep his close-range effort on target.
Choudhury was at fault again when Chelsea snatched the lead in the 46th minute.
When Mason Mount swung a corner towards the far post, Choudhury misjudged his jump and Rudiger got behind him to head in from close range.
It was the perfect way for the German defender to mark his 100th Chelsea appearance as he scored only his fifth goal for the Blues.
But Chelsea's defence remains far from impregnable and Leicester hit back to equalise eight minutes later.
James Maddison found Youri Tielemans and the Belgian's pinpoint pass sent Barnes racing away down the left wing.
Cutting back into the Chelsea area, Barnes tried his luck with a low strike that took a deflection off Andreas Christensen and looped over Caballero into the net for the winger's fourth goal in his last six games.
Chelsea conceded again in the 64th minute as more sloppy defending allowed Leicester to sweep through.
Caballero rashly rushed off his line in a failed attempt to reach an over-hit cross and Chilwell was left unmarked in the area to fire home from Tielemans' pass.
To their credit, Chelsea didn't throw in the towel and Rudiger equalised in the 71st minute, the centre-back rising above Chilwell to power a superb header over Schmeichel from Mount's free-kick.
Leicester should have won it but Jonny Evans headed wide from six yards before Barnes flicked past the far post from close range.