Leeds, despite the loss, retain their position at number three on the standings.
Van Straaten kicked five penalties, closing the gap from 15-3 to 15-12, and then added a fifth kick midway through the second half. But it still was not good enough for Leeds, with Alex King securing a great win by scoring one of his team's two tries.
King opened the scoring with an eighth minute penalty, before he scored the opening try in the 19th minute and added the conversion for a 10-0 lead.
Van Straaten replied with a penalty, before Josh Lewsey stretched the lead to 15-3 in the 39th minute.
Van Straaten added three more penalties, but King kicked what turned out to be the match-winning goal in the 50th minute. Van Straaten concluded the scoring with a 60th minute penalty.
For Leeds:Pens: Van Straaten 5
For Wasps:Tries: King, LewseyCons: King 1Pens: King 2