The Red Devils created plenty of chances throughout the game, but Newcastle remained defensively solid to earn their second point of the new campaign.
Colback told the club's website: "They threw everything at us but we defended really well. The back four and Tim [Krul] were exceptional - every time a ball came into the box, they were first to it.
"Coming here, you will always be defending for a lot of the game. We knew that and we knew we had to see it out. But we were also confident that we would get chances.
"Today we didn't play as well as we would have liked on the ball, but that's what we have to work towards, and it will come. But everyone worked so hard today and we've managed to get a point, which is a positive."
Newcastle face Northampton Town on Tuesday night in the League Cup.