The Magpies fell behind when the Red Devils were the recipients of some good fortune as Steven Taylor's attempted clearance cannoned into Javier Hernandez and past goalkeeper Tim Krul in the 49th minute before they equalised through Ba's 64th minute penalty.
That came about when United defender Rio Ferdinand was adjudged to have brought down Hatem Ben Arfa in a questionable decision but Ba feels the Magpies were due some luck at Old Trafford after the home side's opener.
"My thoughts when we got the penalty was that, after the lucky goal they got, we needed to have a lucky goal as well," he told the Evening Chronicle.
"We got it. We were very happy, even if we did not win.
"We were playing with one man less (following Jonas Gutierrez's dismissal) yet we still kept our shape and gained a result."