Manny Pacquiao and Keith Thurman will collide for the WBA world welterweight title at the MGM Grand Garden Arena in Las Vegas on Saturday with questions hanging over both of them. Let's break down the fight.

Speed

Speed is still a weapon for Manny Pacquiao, right, boxing's only eight-division world titlist. Christian Petersen/Getty Images

Pacquiao (61-7-2, 39 KOs), boxing's only world champion in eight different weight divisions, is 10 years older than the 30-year-old Thurman (29-0, 22 KOs). Logic tells you the older man will be slower with the passing of time. But this is Pacquiao, and even if he has slowed down, it still might be enough to beat Thurman.

This fight comes down to whether Pacquiao, 40, still has the speed, reflexes and aggression that have served him so well in a remarkable career.

Pacquiao has swept through eight weight divisions by throwing fast volleys of punches from all angles, and he will once again try to employ these dazzling skills, albeit at a reduced rate, against Thurman. His footwork, and how fluent it is, will be crucial to the Filipino's chances.

"Boxing is about throwing punches, not who has the bigger body," Pacquiao said. "My speed and power will speak for itself. He may underestimate me now, but he'll talk differently once he's in the ring with me."

Pacquiao, whose blurring hand speed was at its best when he was mesmerizing and knocking out opponents between 2005 to 2012, has shown in his past two fights -- a unanimous points win over Adrien Broner in January and a seventh-round win over Argentina's Lucas Matthysse a year ago -- that he can still overcome younger opponents. That's even after his off night against Jeff Horn two years ago, which cost him the WBO belt in a decision loss -- some say controversially.

Thurman, meanwhile, has had one fight in 28 months, which raises concerns over his speed, sharpness and timing. After beating Danny Garcia by split decision in March 2017, he needed surgery on his right elbow before suffering multiple injuries in a car crash that kept him out until January 2019.

Advantage: Pacquiao

Stamina

Stamina has rarely been an issue for Manny Pacquiao, right. Ethan Miller/Getty Images

Pacquiao and Thurman are not the forces they once were. They both rank below Americans Errol Spence Jr. and Terence Crawford in the welterweight division. Pacquiao was once the pound-for-pound No. 1 in between Floyd Mayweather's retirements, and Thurman was ESPN's No. 1 welterweight two years ago after the well-deserved win over Garcia.

Pacquiao was dreadful against Horn, and the win over Broner was not as emphatic as it would have been five or six years ago. However, he looked better in the wins over Broner and Matthysse than Thurman did in his majority decision victory against Josesito Lopez in January.

Pacquiao has worked hard to combat the effect of ageing, while Thurman has his own questions to answer: Can he be the force he once was after injuries and inactivity? He looked ring rusty in his last fight, in January against Lopez, and opted against a quick ring return to continue sharpening his tools. Against Lopez, Thurman looked decent for the majority of the rounds but had to endure a shaky seventh round. It was not an emphatic win and left doubts as to whether he is back to the form in which he defeated the likes of Garcia.

Despite his years, Pacquiao could still be the fresher, or sharper, of the two and do enough to cause Thurman problems from his southpaw stance.

Advantage: Pacquiao

KO power

Keith Thurman, right, has the power to end a fight with one punch. Al Bello/Getty Images

"Thurman reminds me the most of Ricky Hatton of fighters that I've faced. Will it be the same result? You never know," Pacquiao said.

But a repeat of the same result -- Pacquiao's win over England's hero Hatton in the second round at junior welterweight 10 years ago -- would be a surprise.

For a start, Pacquiao has rendered the judges redundant only once since that night against Hatton. The seventh-round win over Argentina's Matthysse was only the second stoppage/KO win in nearly a decade. Pacquiao, who started his career as a junior flyweight in 1995 when Thurman was 7 years old, went 13 fights without a KO (9 wins, 4 losses).

Then there is Thurman's record, which pre-car crash was enough to make him top dog at welterweight. The Florida resident stopped 4 of 10 opponents before beating Garcia to unify world welterweight titles.

Thurman has the advantage in power, height and reach. Look for him to try to utilize his reach and nullify Pacquiao's energy and punch output. Thurman has predicted he will win by stoppage, and if the fight finishes by KO, it would seem more likely to be delivered by the bigger and more powerful Thurman.

"I'm a real fighter, and Manny Pacquiao is going to get a piece of it," Thurman said. "I was two years out of the game and I still hold the best record in the 147-pound division. You can throw shots and criticism at me if you want. But I bring entertainment to welterweight division."

Advantage: Thurman

Tactics

Keith Thurman, left, has shown he can deal with southpaw fighters like Manny Pacquiao. Brian Blanco/Getty Images

Thurman also showed against Garcia that he can be tactically astute at the highest level.

There is the suspicion that Thurman, trained by Dan Birmingham, can show the same level of ring IQ in world title fights as he did against Garcia, Shawn Porter, Luis Collazo and Robert Guerrero, to outfox Pacquiao, taking advantage of the veteran's recent conservatism and caution.

Collazo and Guerrero were both southpaws, so Thurman has shown he can solve that puzzle, too.

Pacquiao, who trains in Los Angeles with trainer Freddie Roach, could find some openings to strike with counterpunches if Thurman throws a lot of wide shots, as he can do. But Pacquiao has looked a bit conservative in the past few years. This caution could encourage Thurman to be more aggressive and land more.

"For me, his boxing tactics are predictable," Thurman said. "He fights in spurts, and you have to take advantage of that. You have to be respectful of his power.

"But I believe my movement, athleticism and ring knowledge will be able to present him something he's not seen in all his years of boxing."

Advantage: Thurman

Form

Despite losing to Horn three fights ago, Pacquiao enters the fight as the more active, more in form and slight favorite with the bookmakers (Pacman minus-145, Thurman plus-125, according to Caesars Sportsbook). When it comes to experience, and who has beaten better opposition at welterweight, Pacquiao is undoubtedly the pick.

What makes this such a hard fight to call is Pacquiao's age and the truth that fighters can grow old overnight in the ring on fight night. Pacquiao looked like an aging fighter against Horn but has managed a revival since.

If Thurman had been fighting more often, beating top ranked opponents in the past two years since Pacman lost to Horn, then one would be more inclined to wager for him. It makes this is a tough fight to call, one that could well end up being a draw. But based on form, activity and recent performances, Pacquiao just about edges it.

Advantage: Pacquiao

Your take: