Semi Ajayi scored an own goal in Manchester City's 7-0 defeat of Rotherham United on Sunday.
The 25-year-old turned in a Kyle Walker's cross to the roof of his own net on the stroke of half-time.
The goal made it 3-0 for the Citizens after Raheem Sterling and Phil Foden had found the back of the net in the 12th and 43rd minutes respectively.
Gabriel Jesus continued the party for Pep Guardiola's side with the fourth goal in the 52nd minute before Riyad Mahrez notched his eighth goal of the season.
The Algeria international combined with Ilkay Gundogan for a one-two pass before firing a low shot past Marek Rodak in the 73rd minute.
🖐 | Mahrez ➡️ Gündogan ➡️ Mahrez ⚽️ pic.twitter.com/8aN8fdhSA2— The Emirates FA Cup (@EmiratesFACup) January 6, 2019
Nicolas Otamendi and Leroy Sane rounded up the comfortable win for the Etihad Stadium outfit as they progressed to the fourth round of the cup competition.