The Red Devils battled their way to a 0-0 draw at the Stadium of Light with keeper Edwin van der Sar making a vital save from Steed Malbranque and Bolo Zenden hitting a post as the Black Cats dominated before the break.
Either side might have snatched victory at the death, but Ferguson was happy enough with a point on Wearside, their fourth successive Premier League draw on the road.
He said: "Sunderland had the most chances in the game and I have to say we were fantastic defensively.
"That's the area in which we have been leaking goals and throwing games away this season, so I am pleased with that.
"It was a very determined Sunderland team, their home record this season has been very, very good, so I am not pleased but I am satisfied."
Asked about his side's failure to date to win a league game on the road, Ferguson said: "It's a concern, the first three.
"I can't class today's as a disappointment because we had to battle to get the point today.
"But we have thrown the other three away."
Sunderland largely controlled the first half and would have been ahead with 16 minutes gone had Van der Sar not pulled off a fine save to deny Malbranque after he had been played in by Lee Cattermole's excellent through-ball.
But the woodwork came to United's rescue eight minutes before the break when Zenden's long-range strike came back off the post with his former international team-mate beaten.
Nedum Onuoha had earlier seen a close-range effort hacked clear with the visitors struggling.
Ferguson, who had left Wayne Rooney at home and Dimitar Berbatov on the bench, replaced the ineffectual Michael Owen with the Bulgarian at half-time and his side immediately looked more threatening.
Berbatov had a 48th-minute strike correctly ruled out for offside and fired just wide with 10 minutes to go after Simon Mignolet had beaten away Nani's dipping effort.
Titus Bramble unwittingly blocked Nemanja Vidic's injury-time header as United threatened to pull off a smash-and-grab raid, but the spoils were shared.
Ferguson said: "We had no attacking purpose in the first 25 minutes of the match.
"It wasn't until towards the end of the first half that we got any semblance of keeping possession of the ball.
"In the second half we did a lot better, there was more threat by us, but they had chances from set-pieces."