Now Gareth Evans and Derek Adams will be forced to put their past differences aside to now drag Bradford out of League Two.
Both were at the heart of six tempestuous battles between the Blues and Argyle for two seasons.
Evans had been recruited by Paul Cook in the summer of 2015 and was tasked with helping lead Pompey back up the pyramid after their well-documented plummet to the fourth tier.
Adams, meanwhile, was appointed Plymouth boss around the same time and was challenged to deliver promotion at Home Park.
Cook and Adams would be at loggerheads from the first meeting – just two games into the 2015-16 campaign – and their relationship would continue to remain fiery.
In the four clashes that season, Evans featured in each of them – although his involvement in the most important showdown would devastatingly be curtailed.
In the play-off semi-final second leg at Argyle, Evans limped off injured on 31 minutes, with Pompey going one to have their hearts broken via Peter Hartley’s stoppage-time header.
Still, there'd be two more encounters the following campaign after the Pilgrims lost to AFC Wimbledon in the Wembley final. Both were unsurprisingly just as intense – and both ended as stalemates.
Ahead of an Easter Monday clash at Fratton Park, Evans gave a blunt assessment of Plymouth and Adams.
‘I can’t stand them and I don’t like the manager, if I am honest.’
Certainly, no punches were pulled.
The duo would be promoted in 2016-17, although it was the Blues who had most to cheer about.
Pompey the title on the final day of the campaign on goal difference, profiting from Plymouth’s slip-up at Grimsby.
After Cook departed, the friction between both clubs tempered somewhat – although there seemingly was no love lost between Evans and Adams.
Following the Blues' goalless stalemate at Plymouth in April 2018 under Kenny Jackett, Adams claimed his side had dominated the game and deserved three points.
In reply, Evans said: 'We don’t really care what he’s got to say. We know we played well and perhaps he’s trying some mind games.'
Then after Pompey's 1-1 draw at Home Park in February 2019, Adams hit out at Evans' ‘petulance’ and claimed he should have been sent off.
He said: ‘Evans kicked a ball away after he was booked. He has launched it 50 yards out of play and the referee has not booked him.
‘He should have been sent off from that, but the referee chose to give me a yellow card because I protested that he had kicked the ball away after the referee had blown the whistle.
‘If that is the case, I don’t think the referee is correct in his judgement.
‘Evans should have been red-carded. It was an act of petulance and the referee has got that wrong in my view.'
Having been long-standing foes, they'll now have a united cause at Bradford.
Evans returned to Valley Parade after leaving the south coast last September, scoring three goals in 31 games as the Bantams finished an underwhelming 15th in League Two this term.
In contrast, Adam remarkably guided Morecambe to promotion via the play-offs.
He’s now exited the Shrimps and is expected to be announced new Bradford boss imminently – where he will link up with Evans, who has another year remaining on his deal.