The Rebels edged ahead on 38 minutes as Chris Flood fired into the roof of the net after fine work from Warren Harris on the right, who drove into the box and pulled the ball across.
James Dobson then added a second in the final minute of the half, this time Flood turning provider as he beat defender Lee Chaffey and left him grounded before finding the winger in space to apply an easy finish.
Both Slough goals came from counter-attacks, and the half time score was more than a little harsh on the visitors, with Ben Seymour-Shove having been denied spectacularly by Turner moments before the second goal.
Harris should have put the home side ahead within 60 seconds, but he put a free header wide of the post.
But both sides had sights of goal at a hot Arbour Park. Turner made a good save from Jimmy Hartley, and later turned behind a goal-bound free kick from Lewis Hilliard before Dobson’s dipping shot was turned over by St Ives goalkeeper James Goff.
The visitors continued to at least match the Rebels and Hartley brought another good save out of Turner before Flood’s opener.
St Ives started the second half well with Jordan Jarrold chipping narrowly wide, but Slough went on to have by far the better of the play.
It looked to be a matter of time before Slough’s dominance would lead to a third goal, and shortly after Simon Dunn tested Goff with a stinging shot, the Rebels duly killed the game off in the 79th minute.
Flood burst down the right touchline and kept the ball in play in the eyes of the officials – though the visitors were left aggrieved as they claimed the ball had gone out of play. But Slough continued and cut through the St Ives defence as Flood combined with Dobson, with the striker sliding the ball across for substitute Gavin James to finish off a fine team move.
James could have made it four a few minutes from time, but got his finish all wrong from Dobson’s whipped cross.
The Rebels now look ahead to a trip to Farnborough on Bank Holiday Monday.
St Ives Town Line up
James Goff, Brett Longden (Lee Chaffey), Jordan Jarrold, Lewis Ferrell, Charlie De'ath (c), Tom McGowan (Dubi Ogbonna), Lewis Hilliard, Peter Clark, James Hall, Jimmy Hartley (Phil Draycott), Ben Seymour-Shove. Sub not used: Matt Wright.