Four-one up and cruising with an hour gone, Bernard Mendy's goal and a Geovanni penalty left United clinging on in the final frantic minutes to claim a 4-3 win from which they took the points - but Hull will get most of the plaudits.
Not for the first time in recent weeks, Ferguson was left to rue a series of missed opportunities which could eventually prove costly if the title race is eventually settled by goal difference.
"I feel a bit low," said the United boss.
"We should have won by 10 or 11 and we ended up scrambling for a victory. We might have been embarrassed at the end.
"I suppose the only thing to take out of it, apart from the win, is the fact we are creating so many opportunities for ourselves."
Ferguson was fuming at the performance of referee Mike Dean, who he felt was in danger of losing control in the fractious final stages, with Wayne Rooney at particular risk as tempers began to fray.
"It should have been at least a yellow card, in which case the player would have been sent off," said Ferguson. "It made a difference."
Ferguson was also upset at the penalty award for Rio Ferdinand's tug on Mendy's shirt that set up the pulsating finish.
"It was very soft," said the Scot. "Their lad was going away from goal."