After knocking out Derek Brunson in the first round of their headlining clash at UFC Fight Night Melbourne in November, Sydney fighter Robert Whittaker, on a six-fight win streak at middleweight, had a request.

He asked for a challenge, a top five opponent, someone that would test his skills like never before.

This Sunday, at the Sprint Centre in Kansas City, Whittaker gets his wish in the form of one of the most feared fighters in the middleweight division, Ronalda 'Jacare' Souza.

Jacare is Portugese for alligator, and it only takes one look at the Brazilian's resume to figure out how he came to be known by that name.

The 37-year-old is a five-time world jiu jitsu champion, and 17 of his 24 victories have come by way of submission.

After losing his debut way back in 2003, he has lost to just three men: Gegard Mousasi, via an incredibly lucky upkick; Luke Rockhold, by one of the closest unanimous decisions in living memory; and Yoel Romero, by one of the most contentious split decisions in UFC history.

To put it simply, you do not go to the ground with Jacare and expect to win. You could barely be expected to survive, because once the alligator clamps down, he does not let go.

Luckily, Whittaker comes from a country that knows a thing or two about alligators and, come Sunday, the 26-year-old says he has no intention of going to the ground.

His game plan is simple. Stay standing, and put his hands on the Brazilian.

"I've been asking for a top five fighter for a while, I want to test my mettle and I want to test my skill," he said.

"It's hard not to put too much emphasis on his BJJ because he's that good on the ground, but I don't want this to be a jiu jitsu match.

"I'm going in there and I'm going to fight, and I'm going to keep it on the feet.

"You know, Jacare is quick with his hands, sure, but I'm quicker and I'm not going to let him take me down.

"I definitely know that he's going to underestimate me, and I love surprising people when I get in there.

"I'm looking forward to swinging at him."

Talk, as it inevitably does, moves to the makeup of the middleweight division.

Specifically, the chaos the division has been thrown into since the UFC announced that champion Michael Bisping would be welcoming Georges St Pierre back to the Octagon after a nearly four-year absence.

St Pierre deserves an immediate title shot, given his status as a living legend of the sport, but not at middleweight, a division he has never fought in.

A date for the fight hasn't been set, leaving the division in limbo. Romero, the rightful number one contender, has refused to fight anyone else but Bisping.

Luke Rockhold can't seem to get booked for a fight, and Gegard Mousasi – on a five fight win streak – has also demanded a title shot.

Whittaker refused to be drawn on the possibility of being granted a title shot, saying there was literally no future until the fight with Jacare is done, but it wouldn't be an outrageous statement to say he could be the first Australian fighter to get a title shot since Mark Hunt lost 30 kilograms in two weeks to take on Fabricio Werdum for the interim heavyweight title in 2014.

That's where GSP becomes a problem for the young, hungry fighter, and although he's got time on his side – he is the youngest fighter in the top 10 of the middleweight division – he's not afraid to call a spade a spade.

"I'm not too keen on GSP getting the title fight against Bisping," he said.

"I mean he's a legend, an icon of the sport and he can do a lot for the sport, but being honest I'm not too happy he's returning to a division that was never his to begin with.

"He's put the division on hold, but apart from that, I don't want him to return because I like him, and I don't want to have to fight him one day."

In the main event, flyweight champion Demetrious Johnson will edge closer to history when he takes on challenger Wilson Reis.

If he wins, the UFC's pound-for-pound champion will tie with legendary middleweight Anderson Silva for the most consecutive UFC title defences with 10.

It's rarefied air for the man they call Mighty Mouse, who by his own admission has struggled to connect with fans, despite being technically brilliant inside the cage.

Reis, a BJJ champion, has struggled against higher-ranked opponents and shouldn't prove a great challenge to Johnson. The question is not if Mighty Mouse will break Silva's record, but simply when.

UFC Fight Night Kansas City is live on Fox Sports, with the prelims at 8am AEST and the four-fight main card at 10am AEST on Saturday.