Kal Naismith's first goal of the season was enough to see the League Two champions defeat the runners-up at Fratton Park yesterday.
It was a game low on quality although Pompey were the better team overall with Remi Matthews the busier of the two goalkeepers.
Brandan Haunstrup was the first to test him with a fierce drive which was tipped over the crossbar and Matthews then spilled Conor Chaplin's shot over his own goal, foreshadowing the events to come later in the half.
Argyle's best chance of the half came when Yann Songo'o headed the ball wide from close range when unmarked but that was as good as it got for the visitors as they gifted Pompey the only goal of the game.
Naismith then capitalised on a dreadful error from Matthews as he stole possession from him and guided the ball into an unguarded net despite being tugged back. To see the ball agonisingly trickle over the line must have been horrid for the 1,870 fans in the not-quite-sold-out Milton End.
The second saw Matthews make up for his error as he somehow managed to stop Naismith's effort from point blank range after Chaplin did well to tee him up.
There was another excellent opportunity to add a second as Chaplin stole the ball from Antoni Sarcevic and fed Naismith who collided with Matthews after his effort hit the post.
Derek Adams became desperate as his side resorted to pumping long balls into Pompey's box and executing the long throw when they could and although the hosts didn't help themselves by giving away silly free kicks, they were able to see out the six minutes of injury time to get one over their rivals.
It wasn't the greatest performance from Kenny Jackett's men and they've played better and lost this season but they did what they had to do against the worst side to come to Fratton Park this season.
It's certainly no surprise that they're currently the worst team in the league and in real danger of going down. Whilst their style of play may have worked in League Two, it doesn't work in League One and I'll go as far to say if Derek Adams isn't sacked then they'll be making a swift return to the basement division.
Adams' bitterness in his post-match comments made for entertaining reading. It was not an even game despite being settled by a huge mistake as Pompey had the better chances and outfought Argyle in midfield thanks to an outstanding performance from Danny Rose.
The midfielder has set the perfect example of how to make yourself undroppable after being seemingly left out in the cold by Jackett. His all-action displays and willingness to get stuck in have ensured Pompey have been able to dictate play.
Others followed in Rose's example yesterday as Plymouth had the ball stolen from them on numerous occasions and seemed lack the stomach for a fight, which is quite unlike a Derek Adams side.
Even Graham Carey couldn't influence the game for the visitors as Brandan Haunstrup did an excellent job in shackling him on his return to the side. People have been critical about Haunstrup this season but he would have silenced some doubters with his best performance of the season so far.
Yesterday's victory has seen Portsmouth rise all the way up to seventh place in League One, although they are five points behind Charlton who also have two games in hand. The Addicks are Pompey's next opponents in the league and will be a barometer of just how threatening the Blues can be to the play-off positions with over half of the campaign remaining.
At least relegation shouldn't be a worry this season, which is more than can be said for our friends from that dockyard in Devon.
Pompey Player Ratings
Luke McGee: 6 - Little to do.
Nathan Thompson: 7 - Solid return to the side.
Ollie Hawkins: 7 - Looks comfortable at centre back.
Matt Clarke: 7 - Dealt with what Plymouth could throw at him.
Brandan Haunstrup: 8 - Did an excellent job in nullifying Carey.
Danny Rose: 9 - Outstanding.
Ben Close: 7 - Seems to have settled into the side now.
Gareth Evans: 6 - Kept the right side well protected.
Conor Chaplin: 7 - Lively and linked well with Naismith.
Jamal Lowe: 6 - Faded as the second half wore on.
Kal Naismith: 7 - Tenacity won the game and may have had a couple more.
Stuart O'Keefe (Naismith 83): N/A - On because of injury to Naismith. Hopefully it isn't serious.
Matty Kennedy (Hawkins 59): 6 - Worked hard.
Curtis Main (Chaplin 90): N/A - Time eating switch.