Europe are favourites to record a third successive victory in Scotland, but Gallacher believes that Watson will have the players and supporters on his side as they look to upset the odds.
"I thought it was absolutely a masterstroke," the Scot, who captained Europe on three occasions, told BBC Sport. "If anybody can keep the interest going on the American side, [it's Watson].
"It's not just about the players, because the players obviously want to play in the Ryder Cup, but you're really thinking about the American public - keeping them."
Watson captained the USA to victory at The Belfry in 1993, when Gallacher was skipper for Europe.