One day after City announced Pep Guardiola would be taking over from Pellegrini as manager at the end of the season, the Chilean's push for a second Premier League title received impetus from a familiar source as City's matchless Argentine netted after just 16 minutes.
In Pellegrini's 100th Premier League match in charge of City, Aguero's typically composed finish after a deflected cross fell fortuitously at his predatory feet and allowed him take his league goal tally to 13 this season, including a dozen in his last 10 appearances.
Sunderland, suffering in penultimate position in the league, threw everything at City throughout the second half, forcing key saves from Joe Hart after Billy Jones had come closest to equalising just before the break when he hit the post.