Chelsea scored two late goals to secure a stunning London derby win at Arsenal in Mikel Arteta's first home game as Gunners boss.
Pierre-Emerick Aubameyang's 13th Premier League goal of the season, a glancing header following Calum Chambers' flick from Mesut Ozil's corner, put Arsenal ahead at Emirates Stadium.
In a fiesty derby, which saw nine players booked, Chelsea were gifted an equaliser when keeper Bernd Leno missed Mason Mount's free-kick allowing substitute Jorginho to tap home.
Chelsea won it through Tammy Abraham's first-time shot from Willian's pass.
Arsenal, who lost Chambers to injury in the first half, will start 2020 11 points behind fourth-placed Chelsea and without a Premier League home win since 6 October.