Tyrone Barnett scored the only goal of the game as the Cobblers slumped to a 1-0 defeat at the hands of local rivals Peterborough United in a friendly.
The £1m centre-forward provided the game’s decisive moment two-third of the way through a tepid contest at Sixfields.
There was more bad news than good for the Cobblers, with trialist Liam Dickinson leaving the game after just 20 minutes with what looked to be a problem with his ankle.
Dickinson, who is at Northampton attempting to win a contract, missed all of last season after breaking his ankle while with Southend and started this game alongside fellow trialists right-back Kevin Amanwaah and central midfielder Gary Deegan.
Twelve minutes had passed when Lee Tomlin found space down the left and sent in an exocet of a shot from a narrow angle that required a firm wrist from Matt Duke to keep out.
Dickinson’s afternoon ended shortly afterwards, the striker shaking his head as he was withdrawn through injury and replaced by JJ Hooper.
While the substitution might represent the closing of a door for Dickinson, it may come to be the opening of another for Hooper, who got a decent shot away that was well held by Olejnik in a low-key first half.
The second half continued in a similarly slow fashion, with both sides struggling to generate any attacking play of any note.
The breakthrough goal came on 66 when substitute Paddy McCourt slipped a pass to Barnett in the inside-right channel, the £1m striker sweeping his shot past Duke’s right hand.
McCourt then flashed a shot wide after finding space down the right wing as the visitors looked to increase their advantage.
Tomlin was involved in the game’s flashpoint, although he was hardly the guilty party, being dragged to the ground by his throat in an incident that sparked a mass confrontation between both sets of players.
Unlike in the first half, when Ishmel Demontagnac saw yellow for an off-the-ball incident, no cards were shown.
Ian Morris tested Bobby Olejnik with a shot from just inside the box in the final stages of the game and from the resulting long Ben Tozer throw, David Moyo headed wide when well placed.
Further action was limited to midfield sparring and Boothroyd is likely to be pleased with the fact that eight of his players got full matches in.
But he will be dismayed by the injury to Dickinson, which will go down as the game’s main talking point.
Cobblers: Duke, Amankwaah, Tozer, Collins, Widdowson, Demontagnac, Hornby, Carter, Deegan, Morris, Dickinson
Subs: Hooper (for Dickinson 21), Dias (for Hornby 46), Moyo (for Demontagnac 46)
Not used: Snedker, Purse, Reeve, Artell, Roberts
Peterborough: Olejnik, Alcock, Nthle, Bostwick, Payne, Tomlin, McCann, Sinclair, Rowe, Knight-Percival, Barnett
Subs: McCourt (for Payne 61), Kearns (for Nthle 68), Ferdinand (for Tomlin 86)
Not used: Brisley, Swanson, Day, Mendez-Laing, Ajose, Brown, Grant
Away fans: 322