Newcastle United have fired shots at their Tyneside rivals, Sunderland, after Alex Neil left the Black Cats on Sunday afternoon.Just five games into the Championship season, Sunderland have seen their boss poached by Stoke City. And the Magpies were quick to rub in the misfortune of their bitter rivals with a cheeky tweet just hours after his departure.Sunderland had tweeted a snap of Alex Neil with the caption 'Our Gaffer' after the Black Cats beat Stoke earlier this month.