The Senegal international, who will now head off on African Nations Cup duty to leave a huge hole in the Magpies' armoury, gave central defenders Phil Jones and Rio Ferdinand a torrid time to inspire the home side to their first victory over the Red Devils in more than a decade.
Free transfer Ba's 33rd-minute volley, his 15th goal of the season, set Newcastle on their way to a 3-0 win and underlined just what Pardew will be missing for the next few weeks.
The manager said: "His biggest asset is his personality. He's a winner.
"Whatever role I have given him, he has tried to do that to the best of his ability - he has played in two or three roles for me.
"His all-round play has been excellent and tonight, he was a leader for the team and put in a performance to match that.
"When you compare him to other players, it's difficult because really, he hasn't had that long a time here in the Premier League.
"But this year, you would have to put him in the top four or five, for sure."
Ba's first-time strike as he ran on to Shola Ameobi's flick-on handed the home side a half-time lead which they doubled within two minutes of the restart through Yohan Cabaye's stunning free-kick.
United, who had Ferdinand, Ryan Giggs and Wayne Rooney back in the starting line-up, attempted to respond, but barring a remarkable goal-line clearance by Danny Simpson which prevented Rooney from reducing the deficit, rarely looked like dragging themselves back into the contest.
The Magpies completed the job, or at least teenage defender Phil Jones did when he headed keeper Tim Krul's 89th-minute free-kick past Anders Lindegaard to leave the locals in raptures.
Pardew, whose mind was already turning to Saturday's FA Cup third-round clash with Blackburn, said: "The players deserve a lot of plaudits tonight because they have put in some fantastic performances.
"You could highlight one or two that were exceptional, but as the team manager, I am just proud of all of them.
"My job is to make sure we don't get too carried away with that pat on the back because we have got a game in two days' time which is very important to us."
Manchester United boss Sir Alex Ferguson was left to reflect upon a poor evening for his team, but he was philosophical despite witnessing back-to-back league defeats for the first time in 10 months.
He told Sky Sports: "We don't normally have that. The one plus for me was we had two or three players back tonight and hopefully that's them on the road back.
"That will make a difference."