Scott started at five over par, 12 shots behind overnight leader Shane Lowry, but birdied the first two holes as he set the tone for a four-under 32 to surge 41 places by the turn.
That gave hope to the chasing pack behind Lowry, which includes Scott's fellow Australian former world No.1 Jason Day on one under.
So did the outward nine of Sungjae Im, who made five birdies in his first nine holes to record 31, the best score for the front nine this week.
Jason Day was due out shortly after midnight AEST, seeking to close the gap on the leaders. (AP PHOTO)
That lifted the South Korean to two over on a morning when conditions were significantly easier than the opening two days as the treacherous wind dropped.
With rain forecast to hit Scotland's Ayrshire coast on Saturday afternoon, worsening during the leaders' rounds, the possibility of the field closing up kept those behind interested.
Scott rolled in a birdie putt from 14 foot at the first and dropped a near 17-footer at the second. He then scrambled well to par the fourth after landing in a fairway bunker and having to chip out sideways.
A superb tee shot to within five feet at the par-3 fifth delivered a second birdie and the 44-year-old took advantage of a free drop at the seventh to land another, via an 18-foot putt.
Day was due out at 15.15 local time (0015 Sunday AEST) with Lowry and Dan Brown (five under) the last pair out half an hour later.
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