League Two title-winning skipper Doyle has served as assistant coach to Ian Burchnall at the Magpies this season, having hung up his boots at the age of 39.
Meanwhile, Davies, who made 51 appearances and scored once for Pompey, is employed as first-team coach at Paul Hurst’s Grimsby.
Both clubs went head-to-head at Meadow Lane for the right to meet Wrexham in the National League play-off semi-finals.
And it was the Mariners – and Davies – who emerged triumphant from a dramatic fixture, with Mani Dieseruvwe netting the decisive goal in the final minute of extra-time.
Heartbreak for Doyle, with a Magpies side featuring Pompey target Kyle Wootton having earlier looked destined for victory.
County’s Ruben Rodrigues’ second-half penalty appeared decisive, yet Gavan Holohan levelled in the final seconds during six minutes of time added-on to take the match into extra-time.
Then came that stunning finale with a penalty shoot-out looming.
As players, Doyle and Davies were initially team-mates at Sheffield United for 18 months before reunited at Fratton Park in the summer of 2015 for Paul Cook’s first season.
Doyle arrived first and was a key voice in persuading free-agent Davies to join him, initially on a week’s trial.
Subsequently they became room-mates on away trips, while shared a car to and from the midlands as they divided time between families and their south coast playing commitments.
Each voted for the other as their Players’ Player Of The Season as the Blues finished sixth in League Two, before slumping to play-off semi-final elimination to Plymouth.
While Doyle narrowly edged his friend out in a two-horse race for The News/Sports Mail’s Player of the Season for 2015-16.
However, the May 2016 second-leg loss at Plymouth would prove to be their last match as team-mates, with Davies allowed to leave Fratton Park.
Doyle followed him a year later, having totalled 96 games, three goals, and the League Two title during an influential two-year spell.
While Davies finished his playing career at Grimsby, Doyle led Coventry to League Two promotion before seeing out his midfield days with Notts County.
Both have since embarked on coaching careers – albeit with Davies now a step nearer to the Football League.
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