Top Two: UFC 166's most important fights to watch this weekend in Houston

The anticipation for the main event at UFC 166 in Houston, Texas, this weekend (Sat., Oct. 19, 2013) is about to boil over, as Ultimate Fighting Championship (UFC) Heavyweight champion Cain Velasquez looks to make it two straight against his foe -- and the man who viciously knocked him out to take his title away two years ago -- Junior dos Santos.

This will be the third fight between the pair, with "Cigano" winning the first at UFC on Fox 1 and Velasquez victorious in the second at UFC 155 after a five-round drubbing of the Brazilian.

Meanwhile, the "Prelims" mixed martial arts (MMA) under card action on FOX Sports 1 features a potential do-or-die situation in the Welterweight clash between Hector Lombard and Nate Marquardt, both of whom are looking to get back to their winning ways and return to top form.

It's an historic pay-per-view (PPV) trilogy match and a showdown between two former (and fading) 170-pound stars that make up this installment of "Top Two," "UFC 166: "Velasquez vs. Dos Santos 3" edition.

Here we go ...

Cain Velasquez vs. Junior Dos Santos

This fight would conclude the trilogy; however, who can say if the war would indeed be over. Both Heavyweight superstars are entering the prime of their careers, and with the division short of consistent title contenders over the years, these two could meet again after this weekend.

Both men have their shared their reasons for coming up short in their losses. There was talk that Velasquez blew his ACL right before their first meeting at UFC on FOX 1 (where he was viciously knocked out in 64 seconds) and a video depicting the surgery and his struggles was released shortly afterward.

Meanwhile, the recently-released "UFC Primetime" Ep. 1 indicated that dos Santos over trained for their rematch (where he was outmatched for the course of five rounds) and developed rhabdomyolysis. And, for what it's worth, news surfaced that even "Cigano" tore his meniscus in the first fight against Velasquez.

Hopefully, there will be no excuses come Sunday morning and that these two are 100 percent healthy going into this bout.

One could not give the superior striking advantage to dos Santos going into their rubber match since Velasquez rocked him on numerous occasions at UFC 155, but was unable to finish -- or perhaps unwilling -- to score the (technical) knockout finish.

Velasquez will clearly have the grappling and wrestling advantage, meaning that dos Santos has likely drilled takedown defense and grappling with Khetag Pliev -- an Russian Olympic wrestler brought to Brazil for his camp -- to short-circuit this edge.

A product of Javier Mendez's American Kickboxing Academy, Velasquez trains with some of the best talent in the world, including former Strikeforce stars Daniel Cormier (who is the camp's wrestling coach and also fights Roy Nelson on the main card) Luke Rockhold and Josh Thomson, as well as Jon Fitch and Gray Maynard, among others. He is touted as the best Heavyweight on the planet, and rightfully so for his championship accomplishments, possessing uncanny speed and versatility for a competitors of his size.

Dos Santos splits his time with Team Nogueira and Champion Team, having formerly been a member of Blackhouse MMA, home to the Nogueira brothers, Anderson Silva and Lyoto Machida. In other words, his peers are just as impressive. After knocking out Velasquez and defending the title against Frank Mir -- who he also finished at UFC 146 six months after his first fight with the current champion -- many regarded dos Santos, 27 (at the time), as an incredible force for years to come.

It will be interesting to see if this fight will be remotely close to anything we saw in their past two meetings -- more specifically, their outcomes. It is impossible to predict how this fight will go down -- it is virtually a "pick'em" since the champion and the challenger have one a piece on their sides and each was so lopsided.

Either way, UFC 166 will put the discussion to rest once and for all about who is the best Heavyweight fighter on the planet ... at least in 2013.

Nate Marquardt vs. Hector Lombard

Both Marquardt and Lombard have dropped down to Welterweight in hopes of resurrecting the success they had not too long ago at Middleweight, where both men were at the top of the division and considered among the best in the world apart from Silva, who then reigned supreme.

These two are stocky and powerful -- built like muscular cartoon characters -- and the pace of this fight cannot be determined. Both Marquardt and Lombard have stormed out of the gate and scored fast knockouts yet they also were in a few snoozers, too, so who knows if the feeling out process will be overbearing.

It is safe to say that if Marquardt suffers another loss, which would make it three consecutive defeats (not to mention pulling out of a scheduled fight with Rick Story at UFC on Versus 4 two years ago) he would have few -- if any -- chances left with the promotion.

The same could be said for Lombard, who finds himself in a peculiar scenario. During his time with Bellator, he was its dominant 185-pound champion. And many observers called for his presence in the UFC, and more specifically for him to face the aforementioned Silva.

UFC finally acquired Lombard and paid him a ton of money, only for him to lose his debut against Tim Boetsch at UFC 139 in an intensely boring fight. He then went even (1-1) after that, with a win over Rousimar Palhares and a split decision loss against World Series of Fighting (WSOF)-bound Yushin Okami.

"Lighting" has a decorated judo pedigree and is a black belt in Brazilian jiu-jitsu, so he may have the advantages if he decides to look for secondary methods of success besides trading with his opponent. Marquardt also has a black belt under Ricardo Murgel, meaning he is no slouch on the ground either, yet both men have been showing an urge to strike in their recent performances. And if they truly want to dazzle the crowd and their employer, that is exactly what we may be treated to this Saturday on FOX Sports 1 broadcast.

For both Marquardt and Lombard's sakes, let's hope that if nothing else this scrap is entertaining and exciting.

To check out our extensive UFC 166: "Velasquez vs. Dos Santos 3" event coverage click here.