MANCHESTER City's Premier League title hopes were delivered a grievous blow on Sunday as Everton's inspired Romelu Lukaku and teenagers Tom Davies and Ademola Lookman made it another crushing afternoon for Pep Guardiola.

The Spaniard suffered his biggest-ever defeat in league football after City had enjoyed the lion's share of possession and chances but paid for sloppy defending that led to the Belgian powerhouse Lukaku converting his 12th league goal of the season after 34 minutes.

Kevin Mirallas struck right after the break and excellent 18-year-old academy graduate Davies dinked a brilliant first goal for his boyhood club as City looked increasingly clueless.

Substitute Lookman, making his debut at 19, then completed the rout with his first touch in stoppage time, a goal that stemmed from a mistake from Everton old boy John Stones, as City suffered a fourth league defeat in their last eight league matches.

Coming hot on the heels of their last loss in Merseyside at Liverpool on New Year's Eve, City were left in fifth place, now 10 points adrift of leaders Chelsea, as Guardiola cut a forlorn figure on the bench.

"The game is an example of many that has happened this season. It is football. In football you sometimes don't need to do many things to score. They arrive once and score a goal," Guardiola told Sky Sports.

"It is not today, it is almost all the season -- and it is tough for the players to handle that situation. Of course we can do better. It is awful for my players."

His team had started brightly enough and had a strong shout for a penalty turned down minutes later when Raheem Sterling claimed to have been fouled as he tried to round keeper Joel Robles.

Passes from the excellent Kevin De Bruyne set up chances for Sterling and David Silva as the visitors dominated possession but when Davies intercepted a careless Gael Clichy pass out of defence, Everton struck mercilessly.

Davies's through ball picked out Mirallas and his cut-back was met by a first-time left-foot strike from Lukaku, for the Belgian's third goal in his last four matches.

Sterling came close with a searing left-foot strike but Everton pounced straight after the break, Mirallas cracking in a fine right-foot finish after Yaya Toure was pickpocketed in midfield and Ross Barkley offered a neat assist.

Mirallas came off to huge applause to be replaced by Morgan Schneiderlin, making his debut after his midweek move from Manchester United, and it was the signal for the wheels to fall off for City.

Davies, excellent throughout, started and finished the move that saw him clip the ball expertly over the advancing Claudio Bravo, even though Lukaku told the youngster he had got the final touch.

"That (goal) is definitely mine," Davies insisted afterwards with a smile. "It is unbelievable, my dream to actually come in and do this."

Lookman, signed from Charlton Athletic earlier in the month, then produced an even more improbable fairytale in the 94th minute, latching on to the ball after a Stones error to smash his finish through Bravo after being on the pitch for just minutes.