Darron Gibson provided former club Manchester United with a vital boost in the Premier League title race to extend Everton's remarkable hoodoo over Roberto Mancini.
Gibson's first goal since his £500,000 move enabled United to go level on points with Mancini's league leader and ensure City has now only one victory from its last 21 visits to Goodison Park.
The Republic of Ireland international's arrival earlier last month was not warmly welcomed by Everton supporters but this telling contribution could hand the initiative back to his old employer.
City always seem to come unstuck against the Toffees and went into this clash desperate for a fourth successive league win.
Mancini's title-chaser could have been behind after just six minutes but for the presence of a former Everton favourite.
Denis Stracqualarsi's header from Leighton Baines' corner beat Joe Hart but Joleon Lescott hacked the ball off the line before City's defence cleared.
City has stumbled in recent weeks, losing its first two league games of 2012 and exiting both Cups in the space of 17 days. But it was clearly on a mission to end its Everton hoodoo and Gael Clichy, Edin Dzeko and Sergio Aguero all slashed shots wide from decent positions.
At least Moyes can power up his own bid for a top ten finish after the £5.5m signing of Nikica Jelavic from Rangers.
City dominated the early stages of the second half but failed to make the most of its openings.
And Gibson punished its profligacy on the hour to earn instant cult hero status with a drive that deflected off Gareth Barry. It was Gibson's first Premier League goal since March 2010 and time will tell how influential it proves for his old club in the race for the title.
Gibson almost powered in another as City wilted and Mancini's misery was complete when Phil Neville escaped punishment for a clear handball in the penalty area from David Silva's cross.
At the Liberty Stadium, ten-man Chelsea scrambled an injury-time equaliser to deny Swansea a famous victory as the Londoners battled to a 1-1 draw.
Former Chelsea winger Scott Sinclair fired Swansea ahead six minutes before half-time only for Jose Bosingwa's shot to deflect in off Neil Taylor deep into stoppage time to make it 1-1.
The results: Everton 1 (Gibson 60) bt Manchester City 0.
Manchester United 2 (Hernandez 38-pen, Berbatov 53-pen) bt Stoke 0.
Swansea 1 (Sinclair 39) drew with Chelsea 1 (Taylor 90-og).
Tottenham 3 (Bale 29, 64, Modric 34) bt Wigan 1 (McArthur 80).
Wolves 0 lost to Liverpool 3 (Carroll 52, Bellamy 61, Kuyt 78).
