Emotional Frank Lampard rescued a point for champions Manchester City against former club Chelsea on Sunday while Manchester United gave up a 3-1 lead to slump to a shock 5-3 defeat at Leicester.
Lampard's equaliser ensured a 1-1 draw against the Premier League leaders who lost their perfect start to the league season but still moved three points clear of second-placed Southampton.
It seemed Jose Mourinho's side were set for a fifth straight league win when Andre Schurrle put them ahead in the 71st minute, shortly after City had been reduced to 10 men by the sending off of defender Pablo Zabaleta.
But former Chelsea star Lampard, only playing for City after being loaned to them by New York City, the club he left for at the end of last season, drew the hosts level five minutes from time following a typically late run into the box.
"I arrived on one and bounced into the net and it was strange," the midfielder, who spent 13 years with Chelsea, said.
"What was a win for me today? Maybe a draw and keeping the Premier League close and a reception from both sets of fans that I won't forget."
For Chelsea manager Jose Mourinho, the fact Lampard had denied his side victory was immaterial.
"I feel that when a player leaves another club and plays for a direct opponent, he is not going there for a holiday," Mourinho told the BBC.
Meanwhile City manager Manuel Pellegrini was pleased by his side's resilience.
"We continued trying to score, and with one player less trying not to have another counter-attack and concede a goal. I am very happy with the mentality of our team."
The drama at Eastlands was as nothing compared to events earlier in the day at Leicester's King Power Stadium.   
It seemed big-spenders United were on course for their first competitive away victory under Louis van Gaal after goals by Robin van Persie, Angel di Maria and Ander Herrera left them 3-1 up with just over 30 minutes remaining.
But a controversial penalty, converted by David Nugent, reduced the Foxes' deficit to 3-2 after they had got on the scoresheet through Leonardo Ulloa.
Two minutes after Nugent's penalty, Esteban Cambiasso drew Leicester level at 3-3 before Jamie Vardy made it 4-3 in the 79th minute.
Four minutes later, Ulloa made the game safe for promoted Leicester when, after United's Tyler Blackett had been sent off for bringing down Vardy in the box, the striker scored from the penalty spot.
"How is it possible to give this game away?," disbelieving United manager van Gaal told Sky Sports.
"Leicester has proven already in four games that they have a strong character and that when they are 3-1 down, you can play all the game with more possession but you cannot do these kind of things."
- Leicester spirit -
Delighted Leicester boss Nigel Pearson said: "To back up the Stoke win against one of the big forces in English football is very satisfying.
"When you add to that coming from 3-1 down, it is a testament to the quality, belief and spirit amongst us."
United, fresh from their 4-0 thrashing of QPR, like Leicester a newly-promoted side, 2-0 up inside 16 minutes.  
Van Persie opened the scoring in the 13th minute when the Dutch striker headed in Radamel Falcao's cross.
Di Maria then showed why United had paid a British record fee of £59.7 million ($98 million, 75 million euros) to Real Madrid with a sublime second goal, courtesy of a perfect chip over Kasper Schmeichel -- son of United goalkeeping great Peter.
But just two minutes later Leicester pulled a goal back through a near-post header from Argentina's Ulloa headed following an excellent cross by Vardy.
Herrera made it 3-1 before Leicester were given a contentious lifeline in the 62nd minute.
Vardy barged Rafael outside the box but referee Mark Clattenburg let play continue only to point to the penalty spot when the Leicester man went down inside the area following a slight touch by the full-back.
Leicester were all square minutes later when Cambiasso became the third Argentinian to score in the match, with a low shot from inside the box before Ulloa's penalty sealed a memorable win.
West Bromwich Albion and Crystal Palace, who had started the day as the top-flight's bottom two clubs, moved up after 1-0 and 3-2 wins away to Tottenham Hotspur and Everton respectively.
West Brom's James Morrison scored the only goal of the game at White Hart Lane with a 74th-minute header.
At Goodison, Everton's Romelu Lukaku opened the scoring in the ninth minute.
But Palace hit back through Mile Jedinak's penalty and second-half goals from Fraizer Campbell and Yannick Bolassie, with Leighton Baines's 83rd-minute penalty too little, too late for Everton.
Source: AFP