Soh pulled away from the field in the last 2km to retain his title in a time of 2:29.27s.
The former Open champion recorded his second 66 in succession in Greensboro to add to his opening 62 to finish on 16-under par.
Juventus got their Serie A title defence off to a superb start as they demolished Cagliari 3-0 on Saturday.
Wimbledon champion Garbine Muguruza is through to the final of the Western & Southern Open after beating World No 1 Karolina Pliskova in straight sets.
Last year's Bundesliga runners-up RB Leipzig suffered a surprise 2-0 defeat at the hands of a spirited Schalke outfit at the Veltins Arena.
Europe need to make a move at the Solheim Cup after the Americans hung on to their lead in the morning foursomes.
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