The champions ended up only drawing 2-2 after Kim Bo-Kyung headed in a costly equaliser from a free-kick that Moyes felt should not have been conceded. And either side of that agonising moment, United substitute Danny Welbeck and the scorer of the first goal Wayne Rooney missed chances that they might have buried on another afternoon.
"I'm disappointed that we couldn't take the three points," Moyes said. "We gave away a stupid free-kick which led to the [second Cardiff] goal. But we also had a number of chances to put ourselves 3-1 up and we didn't do so, so in the end we've paid the price.
"That's two points dropped in this game and two points dropped in the Southampton game and that can be costly. We've got ourselves to blame [for that]."
The missed chance that many fans will look at was the one created by Ryan Giggs' glorious ball over the top to Rooney after Kim's equaliser. The recipient of the pass elected to feed Welbeck instead of shooting but Cardiff goalkeeper David Marshall intercepted and the opportunity was spurned.
"We actually had two chances in injury-time," noted Moyes. "Wayne had that great chance and Chris Smalling had a half-chance on the turn as well. Before then, Welbeck had a fantastic opportunity [at 2-1] but unfortunately couldn’t