
Junior dos Santos (JDS) is the best striker in the UFC's heavyweight division and, in my opinion, one of the five best strikers in all of MMA (the other four being Aldo, Silva, Rua, and Overeem). Some consider Pat Barry the top striker, but he recently lost to Cro-Cop and did not look nearly as dominant in the striking as JDS was against the same opponent. JDS has been absolutely decimating his opponents. He is one of the most exciting fighters to watch, which has built him sizeable fan base, and there's little doubt that the UFC would like him to get the title shot. Outstriking Cro-Cop over three rounds is a huge accomplishment, even if Cro-Cop is a shadow of his former self. It doesn't hurt that JDS belongs to the same gym as Anderson Silva and Lyoto Machida, two of the elite strikers in all of MMA.
Roy Nelson cannot stand with JDS for very long. Nelson is a competent striker and we've learned that he has knockout power, but he just doesn't have the speed to compete with someone as fast as dos Santos. This means he'll have to try to take him down. In my opinion he'll have an extremely difficult time doing this, again because of dos Santos' quick movement. Nelson defeated good strikers in Schaub and Struve, but he did so not by wrestling but by surprising them with his own striking ability. However, dos Santos is on another level compared to Schaub and Struve; he is far too technical and quick, and if Nelson goes in to the fight thinking he can hold his own for a while in the standup game, he'll most likely be stopped in the first round.
If we look at JDS' UFC victims, one could make a strong argument that he already deserved the title shot (over Shane Carwin). He defeated Werdum, Struve, Filipovic, Yvel and Gonzaga, and he stopped them all with strikes. With the exception of Yvel, these are not middle-of-the-road fighters. And he demolished them. Even against Yvel, who is far too one-dimensional as an MMA fighter, dos Santos outclassed him in that one dimension. Roy Nelson has beaten Schaub and Struve in the UFC. Prior to those fights he was coming off of two consecutive losses. Nelson is a very good fighter, but his momentum is coming mainly from those two wins as well as his performance on The Ultimate Fighter against sub-par competition; a performance which, even in victory, left a lot to be desired.
Suppose for a moment that Nelson manages to take dos Santos down. What then? This is the big question mark, as nobody has managed to test dos Santos on the ground yet. However, Nelson is not a ground and pound specialist. He goes for position and submissions. I don't see this being too much of a problem for dos Santos, who is a brown belt under the Nogueira brothers and should at least manage to take minimal damage and avoid submissions if he ends up on the bottom. If he is taken down he could lose a decision, but the only way this could happen is for Nelson to repeatedly take him down in each round. I just haven't seen the speed or wrestling ability to make me think he'll succeed. Furthermore, as the fight wears on and the fighters tire, Nelson's chances of completing the takedown will diminish. One wouldn't think it by looking at him, but Nelson has good cardio. However, the accumulation of dos Santos' strikes will take their toll on his cardio if they don't put him away. dos Santos only needs to connect with one well-timed punch or combination and the fight could be over.
Two of Nelson's four losses have come against the two best strikers he has faced, Rothwell and Arlovski. While both are great strikers (ok, Rothwell's standup is not great but it's still very dangerous), they are not as quick as JDS and there is no doubt JDS would be the huge favorite against either of them. If Nelson could not handle their striking, there is even less reason to think he'll survive this time. I like Nelson; he's a smart fighter and fun to watch. But I think Nelson's name recognition as an ultimate fighter winner is reflected in the odds, which are overestimating his chances. For Nelson to win, his only path to victory is a three round decision by outwrestling his opponent and avoiding his vicious strikes for three rounds. That would happen less than one out of four times, in my opinion. Even if the fight does go to decision, I dos Santos is more likely to have his hands raised.
Taking dos Santos @-295 means we would expect him to win this matchup more than 74% of the time. That's a high percentage, but given Nelson's limited and unlikely path for victory, I am comfortable with this bet. I believe dos Santos wins this matchup at least three out of four times, and probably closer to four out of five. The edge is with JDS on this one.