In a first half where the goalmouth action was concentrated at the beginning and end, Slough’s recent signing took just 27 seconds to score his first Rebels goal.
Slough broke away and Warren Harris found space down the right, where he played the ball across for Coles to sidefoot home.
St Neots were hampered by the news that striker Lewis Irwin would miss the game through injury, whilst Jack Bradshaw broke down in the warm-up, meaning Liam McDevitt – who was originally named as a substitute – replaced him, leaving the visitors with only one substitute.
And Slough missed good chances to put the game out of reach, with Mark Nisbet heading wide from Matt Lench’s free kick and Chris Flood volleying against a post a minute later.
The game then settled down into a rather turgid affair with the ball spending much of the time in the air or out of play on the sidelines with strong winds playing a big part in the action.
Goalmouth activity increased as the first half drew to a close. St Neots full-back Jonny Herd saw a long-range shot deflected wide, and from the resulting corner the visitors forced the ball into the net, but the effort was disallowed for an obvious foul on Jack Turner.
Nisbet then had a header cleared off the line by former Rebel Luke Knight, but the home side extended their lead a minute later with Coles adding his second. For the second match in a row, a Guy Hollis long throw paid dividends, with James Dobson heading to the back post where Coles had the relatively easy task of nodding it beyond Finlay Iron.
But St Neots responded immediately, and having threatened from a number of corners, made one count with Nabil Sharriff heading home on the stroke of half time to change the complexion of the match.
Slough should really have scored a third early in the second half, but Coles – clean through on goal with just Iron to beat – decided to try and beat the keeper at his near post and complete his hat-trick, but hit the post with an unmarked Flood waiting to his left to apply an easy tap-in.
Joint manager Neil Baker was then sent to the stands by referee James Simpson, his frustration obvious after the Rebels were denied a clear-cut penalty for handball.
With neither side able to create anything clear-cut, the match again fell into a lull with both sides battling the windy conditions. The game remained in the balance, with both sides picking up cautions for a series of niggly fouls.
Flood failed to fully connect with a header from a Dobson free kick delivery, and Iron was able to claim the ball easily. The visitors remained very much in the game, and their best chance of an equaliser came 13 minutes from time, but a brave goalmouth block denied Dion Sembie-Ferris after he was set up by Sharriff.
Slough managed to see the game out after that, aided by the fresh legs of Manny Williams and the returning Simon Dunn, but had one last scare with Sharriff hooking the ball off target after a good move started by Knight in midfield.
St Neots Town Line up
Finlay Iron, Tom Wood, Jonny Herd, Luke Knight, Liam McDevitt, Taylor Parr, Dionne Sembie-Ferris, David Bridges, Nabil Shariff, Dylan Williams, Steffan Broccoli. Unused substitutes: Jack Bradshaw, Dan Buddle.