The Gunners opened the scoring on 18 minutes when Eduardo beat two Pompey defenders before finding Diaby in the box and the midfielder lashed the ball beyond David James.
Arsenal doubled their lead three minutes later and it was Diaby again who produced a cool finish after more good approach play by Eduardo.
Portsmouth were limited to long-range efforts but did pull a goal back on 37 minutes when Younes Kaboul headed home from Nadir Belhadj’s deep cross.
The goal gave Portsmouth hope but six minutes after the restart Arsenal made it 3-1 through William Gallas.
The home side kept up the pressure and increased their lead on 68 minutes when substitute Aaron Ramsey drove the ball home from Robin van Persie’s cross.
Tottenham will have to make a massive offer to land Wilfried Zaha, according to former Crystal Palace chairman Simon Jordan.
Nigel Clough believes keeping Burton in the Championship this season will surpass the achievements of last term's survival.
Garry Monk has challenged his Birmingham players to maintain the high standards they set when beating Hull in their last league game.
Former manager Mark Warburton claims Rangers need to be patient with Graeme Murty or suffer the 'same old problems'.
West Ham's contract with the owners of the London Stadium needs simplifying to put an end to the 'tension' surrounding their tenancy.
Burnley are believed to be leading the chase to sign West Brom defender Craig Dawson in the summer transfer window.