Advantage Arsenal as Man City held in six-goal Everton thriller
The Gunners now just need to win their final three games to end a 22-year wait to become the champions of England.
City remain five points adrift of Mikel Arteta's team, with a game in hand, and will struggle to recover from the manner of their implosion at the Hill Dickinson Stadium.
Pep Guardiola's side appeared to be cruising to victory when Doku opened the scoring at the end of a dominant first half.
However, an error-strewn second period was punished as Thierno Barry scored twice for the Toffees, either side of Jake O'Brien's header.