"We were 2-0 up at half-time and Heurelho Gomes made a save. He quite clearly played the ball first, but they got a penalty."
Defeat for United ended a six-game winning run and gave Tottenham successive league victories at Old Trafford.
Their 3-2 win in September 2012 was their first league triumph at United's ground in almost 24 years.
"We got done on counter attacks," said Moyes. "I thought we were in control. The boys played well and we just could not take the opportunities when they came along."
The January transfer window is now open, but Moyes, who has previously said he does not believe there is good value to be had at this time of the season, said the defeat would have no bearing on his thinking.
"I thought my players did really well," he said. "If I was going to change my mind it wasn't going to be about today."
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