#4. Tim Sylvia vs. Andrei Arlovski – UFC 61

In the summer of 2006, it genuinely seemed like a no-brainer for the UFC to book a trilogy bout between heavyweight stars Tim Sylvia and Andrei Arlovski in the main event of UFC 61.
Not only were the two men clearly the best fighters in their division, but they had also split a pair of previous title fights. More to the point, both of those clashes had been wildly exciting.
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The first had seen Arlovski quickly knock Sylvia down before submitting him with an Achilles lock. The second, meanwhile, saw 'The Pitbull' drop his opponent again – only for Sylvia to somehow will his way back to his feet before turning the tables moments later, knocking Arlovski out to take his title.
Nobody expected their third bout to be anything but another wild slugfest. However, the eventual fight we got couldn't have been much further from that. After two crazy fights, it was clear that not only did both men respect one another, they probably feared the other man's punching power too. That meant both Sylvia and Arlovski fought in a safety-first way, clearly wary of suffering another knockout.
Unfortunately, UFC fans were treated to a slow bout that featured more circling, staring and feinting than the wild exchanges that the two heavyweights had treated them to before.
Sylvia ended up winning a decision after five tepid rounds, but the fight was so bad that his reputation was soiled for good with UFC fans. Arlovski's reputation recovered, but the fight is still remembered as one of the worst title bouts in UFC history.
#3. Anderson Silva vs. Chael Sonnen – UFC 148

2010 treated UFC fans to several titanic battles. However, the fight at the top of the list for most fans that year was the UFC middleweight title bout between Anderson Silva and Chael Sonnen.
Sonnen had talked an immense amount of trash on the longtime champion leading up to the fight. However, to the shock of everyone, when it came down to it, he fully backed up his words.
'The American Gangster' beat Silva down for five straight rounds. He looked set to become the new champion until 'The Spider' somehow pulled out a last-gasp triangle choke with just minutes to go in the final round, forcing Sonnen to tap out.
Sonnen would then test positive for banned substances, putting an end to any talk of an immediate rematch. However, when he returned a year later and won a couple of fights, the UFC wasted no time in booking a second fight between him and Silva.
The hype for the fight – which headlined UFC 148 – was absolutely off the charts, with Dana White even proclaiming it the biggest clash in UFC history. However, it simply couldn't live up to that level of hype, and never came close to matching the sheer insanity of their first meeting.
Sonnen did win the first round, but never beat Silva down as he had in the first fight. In the second round, he attempted an ill-advised spinning backfist that missed. As he slipped to the ground, Silva took advantage and unloaded a series of vicious strikes. Moments later, the fight was over.
This one wasn't a bad fight by any means; in fact, it was fun to watch. However, it didn't come close to matching the original fight, and that meant it came off as a disappointment.