Just when you thought there wasn’t much Max Holloway could do to surprise you, here comes a hay-maker nobody saw coming.

Faster than you can say Khabib Nurmagomedov, Holloway was on a plane to Brooklyn, N.Y., a 12-bout winning streak in tow, to fight the unbeaten lightweight contender Saturday in UFC 223 on six days’ notice.

There is a reason for Holloway’s wide popularity here and abroad, and it is about his what-me-worry fearlessness as much as his ferocity. In a 19-3 career it has so far mattered little who the opponent might be or where the venue is — just point him toward an octagon.

The reigning featherweight champion doesn’t dodge opponents — or the sometimes considerable challenges they present. He charges into them.

Remember his line about venturing into Brazilian Jose Aldo’s Rio de Janeiro backyard in UFC 212? “This is what kings do: Kings go to other kings’ villages and they take over,” Holloway said.

This time he’s battling more than an opponent and his village. It is everything surrounding it. In agreeing to take on Nurmagomedov under the current circumstances, Holloway has gone, well, Max challenge.

Let us count the ways. He’s coming off an ankle injury that sidelined him from last month’s bout against Frankie Edgar. He is moving up to a weight class (from 145 to 155 pounds) he’s never fought at. He’s been away from training and has to drop some weight and is taking on a 25-0 opponent with a disparate, in-your-face wrestling style.

All of which add up to Holloway opening as a considerable 5-1 underdog on the early betting lines.

Holloway is no doubt getting major bucks to jump in and save the show, and definitely winning some major brownie points with UFC owner Dana White, who can’t be too happy with Tony Ferguson (23-3), whose injury withdrawal marked the fourth time he and Nurmagomedov have failed to tangle. One of them coming when Nurmagomedov tried to cut too much weight too soon and had to pull out.

And there is the opportunity to consolidate both his present featherweight title and the lightweight title that is in limbo, which would make Holloway the second in the UFC’s quarter-century history to simultaneously own two belts. He would join Conor McGregor.

Still, it isn’t the kind of role — 11th-hour substitute opponent — or decidedly uphill circumstances somebody who is already an established champion and box office draw usually deigns to accept.

UFC breadwinner McGregor, for instance. As White told ESPN.com on Sunday, “I don’t think Conor McGregor could make the weight on six days’ notice. That’s a tough weight cut for him. And Conor is not the guy I want to throw in as a late replacement fighter. He’s a guy I want to make a fight with and have the right amount of time to promote the fight.”

Saturday’s opponent, Nurmagomedov, was impressed with Holloway’s audacity if not exactly his logic. “For me, I (would) never take this fight,” the Dagestani said Monday on the show “The MMA Hour.” “Why am I going to take this fight? I need eight weeks, training hard, last one week (to) make weight and go to the war. Because when I go to the war, I have to know (whether) I’m ready or no. Because six days? You can’t train. You have to cut weight all six days.”

Which is why, you suspect, there are some pretty hefty, so far unannounced sweeteners to the deal for Holloway.

Like the pledge to make an Aloha Stadium homecoming bout a reality, perhaps? Or, provided Holloway wins, maybe a rematch with the last man to beat him, McGregor?

For all that Holloway has riding on this fight, he’s focused on the potential windfall, doubling down on what has been his approach so far.

Reach Ferd Lewis at flewis@staradvertiser.com or 529-4820.