Keown says Johnson's clash with Manchester City fullback Aleksander Kolarov will be key at Wembley.
He wrote in the Daily Mail: "Sunderland need Adam Johnson to be on top of his game. He'll feel he has something to prove against his old club. For Kolarov, playing against a former team-mate can give you an edge. He has the pace to deal with Johnson, but when the Sunderland player cuts inside, he is tricky to handle."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball