It may, just like the President said, be a very tough four years for Nigeria
For Obasanjo and Tinubu, 2019 presidential elections is beyond Atiku and Buhari, but a case of who runs Nigeria politics from now on.
Buhari said he removed Mr Onnoghen based on an order of the Code of Conduct Tribunal
Obasanjo returned the fireworks on Monday, telling the BBC: "Buhari is sick in the spirit, body and mind."
Obasanjo on Sunday criticised Buhari, accusing him of plotting to rig the elections.
When the man to his left corrected him, saying "gubernatorial", Buhari responded with "to our senatorial candidate".
These are 18 takeaways from the engagement:
Buhari said APC nominated him as its presidential candidate because he had delivered on the campaign promises of the party.