Indeed, Flanagan launched into Sterling to set the tone for a 3-0 win over City early on.
But the 23-year-old says he and the former Liverpool man remain friends.
Flanagan told Sky Sports in an interview aired before Liverpool's 2-1 win over Crystal Palace: "Yeah, Raheem’s a good lad!
"It’s been a relief to be back in the team, I never thought I would be out for that long myself. It’s tough to register being told you’ll be out for a further six to nine months."
Most Liverpool fans, of course, wouldn't exactly call the Manchester City man 'a good lad.'
But Sterling has gone his way and Liverpool theirs, with the future of both promising but far from certain.
If you look at City's season, the Reds really aren't that far behind. Liverpool are only six points behind Sterling's side in the Premier League, while it was honours even before penalties in the Capital One Cup final.
Manchester City ultimately won that final, of course, and have enjoyed Champions League football this term. Next season, though, with Jurgen Klopp and Pep Guardiola facing off once again, it'll be all to play for.