The Englishman took the lead on the second hole with a superb three for a birdie, increasing his lead at the fourth hole with another birdie.
Watson looked nervy, unlike his attitude of the previous two days where he has incited the crowd to urge him on.
Donald led two up at the turn but went on to make it three at the 11th, before a par at the next hole saw him go to within touching distance of Europe's first point of the day.
He had a chance to end the match on the 14th green, but pushed his putt just wide of the cup. Another opportunity went begging at the 15th and Watson survived another hole.
Watson found the bunker with his approach at the 16th, but miraculously holed his pitch out to win the hole and force it to the 17th.
However, his tee shot at the next hole was wild and he had the harder second shot, despite Donald's finding the sand trap.
The European was able to pitch to within inches of the cup and Watson could not repeat his heroics of the previous hole.