Manchester City's Premier League title defence suffered another huge blow in a shock 2-0 defeat to Wolves, while Manchester United endured another miserable day in a 1-0 loss at Newcastle on Sunday.
City now trail runaway leaders Liverpool by eight points after just eight games as Adama Traore punished a sloppy performance by the champions with two goals in the final 10 minutes at the Etihad.
"Today we were not at our level," admitted City boss Pep Guardiola. "We had problems to make our game. We have faced many teams defending deep and found a solution, but not this time."
City badly missed the presence of injured duo Aymeric Laporte and Kevin de Bruyne as Wolves soaked up plenty of possession from the hosts, but always looked the more dangerous side on the counter-attack.
Raul Jimenez failed to make the most of three breakaway chances before the interval, but the Mexican made amends with a great run past the hapless Nicolas Otamendi to set up Traore's opener.
The same two players then combined in stoppage time as Traore raced through to seal a famous win for Wolves.
"The first thing you have to do is stop them and we did that because the players were running like crazy," said a proud Wolves boss Nuno Espirito Santo.
City have now dropped more points at home this season than the entirety of the previous Premier League campaign, but Guardiola is not yet giving up the title fight.
"The distance to Liverpool is big, but we must not think about the eight-point gap. We are still in October and there are lots of games and lots of competitions to play."
TOOTHLESS MAN UTD BEATEN AGAIN
While City's off day came as surprise, United's defeats are becoming ever more routine as they dropped to 12th after failing to win on the road for an 11th straight game.
The Red Devils' lack of a killer instinct in front of goal was again in evidence as Ole Gunnar Solskjaer's men lacked imagination to open up a defensive-minded Magpies.
But Newcastle hit back with devastating effect on the counter-attack 18 minutes from time when 19-year-old Matthew Longstaff sealed a dream Premier League debut by drilling the ball past David de Gea from outside the box.
"We've given ourselves a big, big uphill challenge to get among the top four but it's tight and we need to get a run together," said Solskjaer with United just two points off the relegation zone and five outside the top four.
However, De Gea was more scathing in his assessment.
"We didn't create any proper chances," said the Spaniard.
"We have some big injuries but that's no excuse. We are Manchester United, we need to keep training hard, fighting and winning games."
ARSENAL UP TO THIRD
Arsenal were also far from convincing but did enough to edge out Bournemouth 1-0 thanks to David Luiz's first goal for the club to move into third.
The Gunners were lucky to escape as Bournemouth enjoyed by far the better chances after the break with England striker Callum Wilson somehow failing to find the net after rounding Bernd Leno.
"We are very happy with that result. I'm very proud with our work in the first-half, but we are very critical with ourselves to improve things," said Arsenal boss Unai Emery.
Chelsea boss Frank Lampard was much happier after his side rounded off an excellent week with a 4-1 win at Southampton to remain just one point behind Arsenal in fifth.
Tammy Abraham and Mason Mount put the Blues in command early on at St. Mary's before Danny Ings pulled a goal back for Saints.
However, N'Golo Kante quickly restored Chelsea's two-goal lead and Michy Batshuayi came off the bench to round off the scoring and the Londoners' third win in eight days a minute from time.
Abraham now has eight goals in eight Premier League appearances this season and nine in all competitions.
"I trusted him at the start of the season," said Lampard. "He also has (Olivier) Giroud and Batshuayi there, and he has made the place his own at the moment. I will keep on him because I want more."
•Text (excluding amended headline) courtesy of AFP.