Williams put Salt Lake up 2-0 just before the half after collecting the ball at the top of the Toronto area and firing it into the top-right corner.
The other goal for Real Salt Lake (2-3-1) was credited to defender Jamison Olave in the 14th minute. Alvaro Saborio headed toward goal off a corner kick and Olave got into position to get a toe on the shot, directing it across the goal line.
Toronto (2-4-0) got its only goal seconds before the end of the game when Dwayne De Rosario converted a penalty kick triggered by a Kyle Beckerman handball in the box.
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