In her phone call Victoria Nuland expressed a desire for Arseniy Yatsenyuk to win, specifically she says:
"Yats" (i.e., Arseniy Yatsenyuk) is our guy
Arseniy Yatsenyuk did not win the presidency, despite the fact that this was her expressed desire. If the US was controlling who the winners and losers are, why didn't they get "their guy"? Instead Turchynov became interim president for about 4 months before being replaced by Petro Poroshenko.