Following Brock Lesnar\’s UFC 100 victory over Frank Mir, many new fans to the sport are under the mistaken impression that he\’s unbeatable. In his short tenure as a professional fighter, the former WWE champion has seen a remarkable transformation in public opinion from the suggestion that he\’s a \’sideshow freak\’ to the misconception that he\’s \’unbeatable\’. With all due respect to Lesnar, who is progressing by leaps and bounds as a fighter with every bout, hes got a big deficit in experience to make up on the job as UFC heavyweight champion.

Lesnar is no doubt a tough matchup, but he\’s been the beneficiary of very favorable matchups in his short professional career. Lesnar has made amazing progress as a fighter, but he\’s not unbeatable. Here\’s fight fighters who could do it.

1) FEDOR EMELIANENKO: \’The Last Emperor\’ is until proven otherwise the best heavyweight in the sport. The former PRIDE champion has striking power, submission mastery, and may be the toughest fighter mentally in the sport. Fedor might get taken down by the new UFC heavyweight champ, but hed reverse it from the bottom and win via armbar.

2) ANTONIO RODRIGO NOGUEIRA: Nogueira would present Lesnar with another formidable challenge. The former Interim heavyweight champion has equal, if not superior, BJJ skills and has proven to be tougher and more durable than Mir. His five career losses are all via decision and came to the absolute highest level of competition (Fedor Emelianenko twice, Frank Mir, Josh Barnett and Dan Henderson). The UFC heavyweight division is notoriously thin, but among the current crop Nogueira is by far Lesnars worst matchup.

3) JOSH BARNETT: Barnett is another unlikely opponent for Lesnar, due as much to his recent positive drug test in California than anything else. Still, Barnett could be the worst matchup in the sport for the new UFC champ. Lesnar is likely the more powerful of the two, but Barnett is an imposing physical presence himself at 63 250 lbs. Barnett also has a solid wrestling background, with the added dimension of his sizable submission repertoire. As his career has progressed, Barnett has become a more patient and tactically sound fighter and his standup game has improved significantly. Perhaps Barnett\’s greatest weapon against Lesnar is his wide knowledge of \’shoot wrestling\’ submissions that are very effective and tough to learn how to defend.

4) ALISTAIR OVEREEM: Overeem is bigger than Lesnar\”260 pounds and 65 tall. He went through a rough patch in his career during his tenure in PRIDE, but has compiled a 5-1-1 record in his last seven fights. Mirko Cro Cop suggests that hes the *only* fighter in the world who could beat Fedor Emelianenko at this point. Hes got great standup including a kickboxing background that could cause Lesnar problems, as well as solid ground fighting ability. Hes yet another heavyweight that is unlikely to bend to Dana Whites contractual demands, and currently has a relationship with DREAM in Japan and Strikeforce in the US. Still, hes a dangerous matchup for any fighter on the planet.

5) RANDY COUTURE: Lesnars win over Couture was far from decisive, and it didnt have anything to do with the age disparity. Couture got caught with a big shot and it cost him the fight. Until that point, he was more than holding his own. He was making his opponent work hard, had the edge in the striking exchanges and had opened up a cut over Lesnars right eye. Itll never be a favorable physical matchup on paper for Couture but at the same time Lesnar in no way proved his categorical superiority over The Natural

An intriguing matchup down the road could be against Croatian striking machine Mirko Cro Cop. Cro Cop has battled injuries over the past year or so but if he could come close to the form he demonstrated in winning the PRIDE Open Weight GP he could be another formidable challenge. At his best, Cro Cop is simply the most devastating striker in the sport.