The Dutchman and Chicharito were both guilty of profligacy against Real Sociedad as the visitors missed the chance to take control of their Champions League group
The Dutchman came off the bench to replace Wayne Rooney with the match scoreless, only to hit the woodwork from 12 yards before again being denied by the upright late on.
But Moyes is certain van Persie will not be deterred, despite failing to add to his solitary goal so far in Europe this season.
"The goals will come for Robin, he's scoring already so hopefully more will come," he told Sky Sports.
Chicharito was also guilty of profligacy, and United's disappointment was compounded in the closing minutes of the match when Marouane Fellaini was sent off, but Moyes remains confident of qualification for the knockout stage.
"It shouldn't have been a draw, it should've been a victory. We played well enough to win the game," he said.
"We had a lot of chances and missed a penalty as well. It was [concerning] because when you get opportunities you want to take them. They would have ensured that we went well clear at the top of this group."
The Scot also leapt to the defense of Fellaini, insisting that the Belgium international was unlucky to be shown a second yellow card for a late challenge.
"I think there were some strange decisions, and that was one of them," the United boss added.
"I think it was just a case of totting up [the challenges] at the end of the day that got him the sending off. It was harsh, as he played well."