A power cut prior to the game threatened the possibility of it taking place as fans travelled through a Bristol blackout to get to the match, but emergency generators had power restored and the game kicked off in time.
An unchanged Portsmouth team performed well and didn't deserve to lose on balance of play having dominated possession for periods of the game. Unfortunately, Pompey lacked that killer touch, left the back door open on two occasions and were made to pay the price.
Pompey's passing was much better than it had been in previous games and the hosts were given plenty of trouble by former Robin David Cotterill and by David Nugent on the other side of the attack.
Keith Millen's men were playing like a typical away team by soaking up pressure and attempting to hit Pompey on the counter-attack.
That almost worked after Pompey were caught short and the ball fell to David Clarkson who netted the rebound after Jamie Ashdown saved Nicky Maynard's initial shot, only for the offside flag to deny him.
That meant that Ashdown had broken Peter Mellor's post-war record of minutes without conceding a goal but the all-time record would be denied just five minutes after Mellor's record was broken.
Ricardo Rocha decided to go on a run upfield and was caught in possession, leaving a gap in a defence that he had marshalled very well until then. Albert Adomah and Maynard sprinted forward and exchanged passes with each other so Adomah could slot the ball home.
Pompey should have equalised immediately after Joel Ward headed over Nugent's cross after David James had come rushing out of his goal, leaving it completely unguarded.
Steve Cotterill's men dominated possession as the second half began, pinning City in their own half without ever forcing David James into a meaningful save.
However, Pompey were hit with the sucker-punch as they were caught short at the back again and Maynard struck a ball across the box that had "own goal" written all over it and so it was as Greg Halford put the ball past Ashdown.
The game lulled for a while after that but Pompey never gave up and Dave Kitson had the last of their chances. He probably should have scored when James presented him with the ball, only for him to lob it over the bar instead of the 'keeper.
James then denied Kitson again with a superb save to keep out his fierce drive but the Pompey striker would find the net in stoppage time after turning in Carl Dickinson's shot.
There was no second goal to come as City dealt with the final long throw of the game to confirm Pompey's first defeat in seven matches.
Whilst it was disappointing to taste defeat for the first time since early February, I can't fault the players for the performance as there was plenty of zest going forward and we were relatively untroubled at the back until a counter-attack left the rearguard exposed.
We have performed much worse than that this season and won, but that's football, isn't it? If the players can reproduce that sort of performance and add a killer touch when Middlesbrough visit Fratton Park this Saturday, then I'm confident this defeat will just be an unfortunate blip in what has otherwise been an excellent run.
Pompey Player Ratings
Jamie Ashdown: 6 - No chance with either goal.
Ritchie De Laet: 6 - Worked well with Cotterill.
Greg Halford: 6 - Unfortunate.
Ricardo Rocha: 7 - Excellent apart from that one costly run.
Hermann Hreidarsson: 6 - Tough battler against City's wingers.
Jonathan Hogg: 6 - In and out of the game.
Hayden Mullins: 6 - Did the usual job.
David Cotterill: 7 - A constant threat.
Joel Ward: 6 - Should have scored.
David Nugent: 7 - Created chances for team mates.
Dave Kitson: 6 - Getting better.
Substitutes
Darryl Flahavan
Carl Dickinson (Hreidarsson 84): N/A - Late shot led to goal.
Aaron Mokoena (Rocha 87): N/A - Presumably brought on to protect Rocha.
Tom Kilbey
Kanu (Ward 90): N/A - Made a difference, should have been brought on earlier.