UFC Fight Night 90 preview: Alvarez stands in the way of greatness

At UFC Fight Night 90, lightweight champion Rafael dos Anjos and Eddie Alvarez become the first male fighters to compete for a world title exclusively on the online Fight Pass service.

It's a far cry from the PPV main event that Dos Anjos almost had against Conor McGregor this past March, but don't expect him to look past Alvarez as he seeks his second successful title defense.

The heavyweight title is often presented as an example of impermanence, but the lightweight belt has also proven difficult to hold on to. No fighter has managed to successfully defend it more than three times.

Alvarez could be the man to abruptly stop Dos Anjos' championship run, especially if he returns to the fight-finishing ways that once made him the most feared lightweight outside of the UFC.

Here are three other stories to watch Thursday:

Is 'The Black Beast' a legitimate threat in the heavyweight division?

Derrick Lewis could be the heavyweight that the UFC needs to inject some new blood into the top 10.

For the most part, the same names have been shuffling around the upper echelon of the division for the last few years. The "freshest" name in the top 10 is Travis Browne, a 33-year-old who has been with the company for six years.

Lewis turned 31 in February and he's made a name for himself as the most active big man in the business by fighting nine times since the start of 2014. No other UFC heavyweight has made five appearances in that span.

He's developed a cult following due to his violent finishes and quirky online persona. If he can beat the popular Roy Nelson on Thursday, it will show that he's more than an amusing curiosity.

'Irish Joe' ready to move past McGregor

Let's just get this out of the way: Yes, Joseph Duffy has a win over Conor McGregor.

Duffy eventually joined his fellow Irishman in the UFC, finishing his first two opponents in the first round. He was given a step up in competition against Dustin Poirier at UFC 195 this past January and dropped a decision for his first loss inside the Octagon.

It was an entertaining tilt that likely would have been the Fight of the Night were it not for the classic Robbie Lawler-Carlos Condit encounter that occurred later that evening.

If Duffy wants to carve out a legacy beyond the McGregor win, he'll have to have a good showing against Mitch Clarke in Thursday's main-card opener. Clarke is a stiff test, exactly the kind of opponent that will gauge where Duffy stands in one of the UFC's deepest divisions.

Prelims shine a light on international talent

The first Fight Pass event to host a UFC title bout was last June, a meeting between strawweight champion Joanna Jedrzejczyk and Jessica Penne. It took place in Berlin, Germany, making it an ideal opportunity to showcase the sport's international talent.

That theme carried over to this week's card in Las Vegas, with 13 of the 24 fighters on the card hailing from outside the U.S.

Brazil is well-represented by Dos Anjos, as well as preliminary fighters Alberto Mina, Dileno Lopes, Pedro Munhoz, Felipe Arantes, Gilbert Burns, and Reginaldo Vieira.

Canada (Clarke, John Makdessi) and Mexico (Marco Beltran, Alvaro Herrera) send two fighters each, while Ireland (Duffy), France (Mehdi Baghdad), and Poland (Lukasz Sajewski) will also take part.