It wasn't even a tussle. On that play (first-and-goal from the 3), the Vikings wanted to run a quick fade to Moss, but he stumbled and fell down. Culpepper was about to throw it, but when he saw Moss fall, he pulled the ball down and scrambled out of the pocket to his left (the other side of the field). When Newman saw Culpepper scramble, he jumped on Moss and kept pushing him down to keep him from getting up (which is perfectly legal once the quarterback leaves the pocket). Moss, though, didn't appreciate it and started pushing back and Newman. Then the refs came over, and Newman put his hands up, stood up and let Moss get up.
That's it. There were no punches thrown, and it had nothing to do with Newman being frustrated or anything.
On the next play, Moss pushed off, caught a hook at the goal line and got tackled out by the 2-yard line, but the ball had broken the plane of the goal when he caught it.
Moss finished that game with two catches for 4 yards against Newman -- both of them were touchdowns (3 yards, 1 yard). Moss also had a 13-yard catch against Pete Hunter and a 10-yard catch against Hunter and Tony Dixon.