Teenager Danny Cadamarteri shone in Everton's Merseyside derby victory over Liverpool at Goodison Park.
His goal followed a Neil Ruddock own-goal that gave the hosts the lead on the stroke of half-time.
Victory moved Everton up to 16th with 11 points, two points above the relegation zone while Liverpool dropped to ninth on 15 points.
Chelsea goalkeeper Carlo Cudicini gifted Arsenal all three points with a costly error at Highbury.
With 15 minutes left, Cudicini fumbled a Robert Pires cross into the path of Thierry Henry, leaving the Frenchman a simple finish.
Arsenal had previously led through an Edu goal before Hernan Crespo's shot flew into a top corner to make it 1-1.
Victory moved Arsenal top with 23 points, while Chelsea dropped down to third, three points behind the Gunners.