Holt reacted quickest after stand-in goalkeeper Vito Mannone had spilled Alex Tettey's 25-yard effort midway through the first half to slot his third goal in successive games.
"It is all about hard work and we have been putting the same endeavour in but not getting the rewards. We will take a lot from this result.
"No-one will have given us a chance of winning this and wrote us off too easily.
"We needed it and it has taken a while for us to wait for the performance and the win.
"We have to realise that is the only way we are going to get results in this division. If we keep doing it, then we will be all right."