The south coast club’s owners, Convers Sport Initiatives, went into administration last week, sparking fears that Pompey could be plunged into financial turmoil once more.
Manager Michael Appleton insisted on Friday that his players would be paid on time and they responded by delivering his first win since taking charge, Joel Ward netting the winner at Fratton Park.
Greg Halford opened the scoring with a 20th-minute penalty following a calamitous piece of defending from the visitors, who sink to the foot of the table despite drawing level through Lukas Jutkiewicz.
The warning signs were there for the Sky Blues as early as the third minute, when Dave Kitson’s powerful long-range volley forced a good save from Joe Murphy.
Gary Gardner did well to clear under pressure from Ward following Joe Mattock’s teasing delivery shortly afterwards.
At the other end, Gardner blazed an ambitious free-kick wide of the left upright as Andy Thorn’s side momentarily relieved the pressure.
They dropped themselves right back in it, however, when a mix-up between Martin Cranie, Richard Wood and Murphy which saw the latter trip Ward.
After consulting with his linesman, referee Carl Boyeson pointed to the spot and Halford sent Murphy the wrong way to put Pompey ahead after 20 minutes.
The goal stirred Coventry into life and they almost provided a decisive response when Sammy Clingan delivered for Jutkiewicz but his cushioned header was just beyond the reach of Clive Platt.
Andy Keogh powered through the middle moments later but was dispossessed by Ricardo Rocha. Portsmouth broke immediately and Erik Huseklepp’s deflected shot fell kindly for Kitson, who somehow fired wide.
Appleton’s side almost pressed the self-destruct button just before half-time as Halford sloppily conceded possession in his own half, allowing Jutkiewicz to break away but his cut-back for Platt was easily gathered by Stephen Henderson.
But they were not to be denied and nine minutes after the restart, Wood’s superb left-wing cross was turned home by Jutkiewicz.
Any hopes of building on that platform were shattered when Portsmouth took a quick free-kick and George Thorne’s clever pass found Ward, who fired across goal and into the bottom corner from the edge of the box.
The scores should have been level after 71 minutes when Keogh fed substitute Gary McSheffrey but he was denied by Henderson when lifting his shot would surely have seen him score.
Thorn’s men were made to rue the missed chance as they saw their winless run extended to 10 matches.
Portsmouth’s future remains uncertain but the win pulls them three points clear of the relegation zone and 10 ahead of Coventry.