If you ask me, I would think that Theodore Long would have to make this submission match, no DQ or countout. I mean, C.M. Punk has been crossing paths with Long for several weeks now, and with Long knowing that Punk might try to take the easy way out, he should automatically make it no DQ or countout, but only for Punk. This way, if Punk wins, he'll win legitimately or if Punk loses, then he can make it seem like it was all Theodore Long and The Undertaker's fault, for screwing him.
To be honest, I don't see why Undertaker should lose in his first ppv back. On the other hand, I don't see C.M. Punk losing the title in the next ppv after he won it. Even though it isn't going to be his 1st title defense. When Undertaker returned at Wrestlemania XX, he won against Kane. When he returned at Unforgiven 2007, he won against Mark Henry. So, you'd think that he would have to win this match. However this is a title match, and as it's been shown in the past, Undertaker has to be screwed out of the title many times before he wins it.
I think that The Undertaker needs the title a lot more than C.M. Punk does. Sure, Punk needs credibility as the champion, but Punk will be in the WWE for years after Undertaker is retired. And Undertaker needs to cement his already impress legacy with a nice dominant title reign. Even if it's very late in his career. C.M. Punk can have many title reigns in the future, but this fued with The Undertaker is a one time thing. Whether Punk is on the winning or losing end of the fued, it will still give Punk credibility because he is in the same ring as him. A loss against The Undertaker doesn't hurt anybody really.
The Undertaker has his "Devil's Triangle", and has learned to perfect it. C.M. Punk hasn't used his "Anaconda Vice" in over two years, but now would be as good a time as ever to bring it back. It looks very devastating, and if Undertaker were to tap out to it (PLEASE NO), I wouldn't be surprised. So, I'd say that The Undertaker should win this match, but WWE, assuming that they are having plans to have Taker win the title soon, will likely stall the title win, just to extend Punk's reign.
Prediction: C.M. Punk finds a way to retain the World Heavyweight Championship.