Kenny Jackett revealed Pompey’s FA Cup clash at Harrogate Town came within ‘10-15 minutes’ of being scrapped.
The Wetherby Road ground was plunged into darkness twice before kick-off following power cuts.
Last night’s first-round encounter finally started at 8.40pm – following a 55-minute delay.
For long periods, the emergency lighting was solely in use as maintenance staff battled away to restore full power to the non-leaguers’ stadium.
When the fixture finally got underway, the Blues ran out 2-1 winners in front of the BT Sport cameras.
But the match very nearly didn’t take place, with time running out to fix the frustrating power issues.
Jackett said: ‘We were kept informed. The referee, along with the Harrogate manager, and then, ultimately, BT Sport were in constant communication and assessment.
‘Another 10-15 minutes and it would have been called off, there was a point around about 8.30pm that it was make or break.
‘I am pleased to say the referee kept his composure, we started and the lights stayed fine all the way through.
‘When the match did begin, the players dug in, showed character and scored two excellent goals.
‘But early on we didn’t get to grips with them, down the slope with the elements behind them, it was tough for us, we didn’t deal with it very well.’
Pompey struggled to come to terms with the 3G playing surface, while Tom Naylor and Sean Raggett both went off in the first-half with muscle injuries.
Jackett added: ‘It is what it is, you don’t want it make the surface an excuse, but obviously Harrogate play on it all of the time, so it is always going to be a slight advantage.
‘However, we made sure our attitude was right and, during the course of the game, found a way to win and we adapted.
‘It was always going to be a difficult game, but we found a way, which I am very pleased with.
‘Our system, the 4-2-3-1, was exactly the same as usual, however there's a degree of playing the elements which took us a little while to get to grips with.’