Former Manchester United midfielder Darron Gibson boosted his old club's title chances by firing Everton to a stunning 1-0 win over Manchester City.
Gibson lashed home his first goal since quitting Old Trafford earlier this month as the Barclays Premier League leaders slipped up at Goodison Park.
The visitors hit the bar in the first half through Samir Nasri but Everton, who earlier saw a Denis Stracqualursi effort cleared off the line, again proved stubborn opposition for City.
City had won just one of their previous 13 league visits to Everton and the extension of that poor record left them top of the table only on goal difference.
Manager Roberto Mancini was again frustrated by another controversial decision as his team were denied a late penalty for handball by Phil Neville but referee Peter Walton ruled any contact accidental.
Stracqualursi came close to putting Everton in front but Joleon Lescott headed off the line with five minutes gone before Nasri struck the bar with a crisp 30-yard shot.
Play was held up just before the interval when a man ran into City goalkeeper Joe Hart's goalmouth at the Park End and handcuffed himself to one of the posts. He was removed by police and led away after a short struggle but Walton played five minutes of stoppage time.
Everton made City pay for their failure to take advantage of their possession as they made the breakthrough just before the hour.
Leighton Baines found Landon Donovan in space with a deep cross into the box. The American calmly laid off the ball for the inrushing Gibson, who fired in from the edge of the box - via a deflection off Gareth Barry.
City appealed for a penalty for handball after substitute Aleksandar Kolarov hit the ball at Neville but Walton saw nothing untoward and the hosts held on for a precious three points.