The 22-year-old Frenchman left Old Trafford during the summer after two frustrating seasons, but is now enjoying regular football in the North East.
He said: "I think my last game against Stoke was my best game for the club so far, so I think I am getting the tempo of the Premier League and I am getting to know my team-mates better as well, so everything is working fine.
"I just need to maybe score a few goals now and to keep making assists, and it will be great.
"It's only been 10 games, so I think I can do a lot better. That's the way I think, and hopefully I will do it."
Obertan arrived at United during the summer of 2009, but made just 13 senior starts as he struggled to force his way into Sir Alex Ferguson's plans on a sustained basis.
He said: "It's never nice to leave such a club. There might be some regret, but after the start we have had, I can't have those regrets anymore because after 12 games, we are still in the top six. It's just great."
Asked if he feels he has a point to prove tomorrow, Obertan said: "In a way, yes.
"When you leave a club, you always have that feeling - when you go back there, you want to prove that you are a better player, and I will try to do it.
"But before that, if we can get three points, that's the main thing."