When entering the rematch of a close and contentious first fight, it can often be difficult to determine which boxer has more pressure upon them the second time around. 

Considering what's at stake for him to protect on Saturday, it would be natural to assume that Andre Ward would be most feeling the heat entering his rematch with Sergey Kovalev at the Mandalay Bay in Las Vegas (HBO PPV, 9 p.m. ET).

Ward (31-0, 15 KOs) is not only defending his unbeaten record, top pound-for-pound ranking and trio of 175-pound belts, he'll be forced to prove his controversial win last November was justified with a performance that leaves no doubt. 

The unanimous decision victory turned in by Ward (114-113 on all three scorecards) was arguably the most contested decision the sport has seen in recent years. While more people thought Kovalev had won, and some went as far as calling it a robbery, many fans and critics were split, which was something the equally contentious first fight between Manny Pacquiao and Timothy Bradley Jr. in 2012 couldn't claim. 

But while Ward has pressure on Saturday to maintain the more tangible rewards that came with winning the first fight, Kovalev (30-1-1, 26 KOs) must defend something altogether more important: his reputation as not just a destroyer but as quite possibly the sport's most complete fighter.

That's the title most hanging in the balance entering Saturday, the idea that Ward may have exposed not just a tactical weakness to Kovalev's game but, even worse, a front-running and bully mentality that was quick to make excuses in defeat. That, along with the burden of keeping the fight out of the three judges' hands at ringside, places Kovalev firmly on the hot seat. 

It's a theory Ward, 33, has done his best to perpetuate in the buildup to the rematch. 

"You've got to realize, I've been boxing for 23 years. I just fought this man for 12 rounds and contrary to what may be out there, there's nothing scary about him," Ward said. "He didn't knock me down in the ninth and tenth round and I'm holding on for dear life and, 'Oh my God, I barely made it.' 

"He knocked me down in the second round and if you watch the rest of that fight, I didn't go into survival mode, I didn't go into self-preservation mode. I went into 'it's going to be me or you' mode. And I don't feel like 'The Krusher' responded the way that many thought he was going to respond. Contrary to what's out there, boxing is a thinking man's game."

Ward, the smaller fighter, got up off the canvas following that second-round knockdown on a punch that would've have finished most opponents. From there, he slowly made adjustments, weakening Kovalev over time by going to the body, while deftly closing the distance to disarm Kovalev, a rangy fighter who's more dangerous from the outside, of his stinging jab and powerful right hand. 

Regardless of who you felt won the series of close rounds over the second half of the fight, it's difficult to deny Ward's ring generalship in the sense that he forced Kovalev to fight at a pace and style he didn't want to. In the end, Kovalev, 34, not only lost the battle in terms of the decision, he ultimately lost the war by fading late and proving unable to adjust. 

Kovalev is about to prove the first fight was a poor decision by the judges. Getty Images

The performance was a stark contrast to the momentum Kovalev created since first making his HBO debut in 2013, when he knocked out Nathan Cleverly in England to win his first world title. The dominant performance kicked off a string of nine victories, including seven by knockout, as Kovalev made his claim for consideration as the best fighter in the world. 

Ward not only proved to be Kryptonite for Kovalev's offense once he adjusted, he kept coming back after getting up off the deck, which can have a hand in playing against a big puncher's psyche when he's unable to finish an opponent off. 

It's because of this that Kovalev has more questions to answer in their second fight. To do so, he has promised to be more aggressive, which should make the first half of the fight in particular a tense game of chess for Ward. 

But the fact that Kovalev, throughout the promotion to the fight, hasn't acknowledged any success that Ward had against him or admitted anything needs to change in terms of his approach, other than not overtraining, could be a red flag in terms of the outcome. 

If Kovalev can come out more aggressive and walk Ward down and finish the job, the point will be proven moot. But if the Russian slugger gets caught in another tactical boxing match over the second half of the fight, Ward is the wrong opponent to play chess with. 

"I don't really feel that [Ward] did much. I didn't even pay attention to him in the ring," Kovalev said. "He wasn't a danger for me. I was more fighting for myself because I was so tired.

"I think everybody saw what happened [in the first fight]. I boxed against a whole team called Ward, not just Ward. I don't want the fight to go to the judges again. I want to make sure this time." 

By activating his rematch clause, Kovalev has an opportunity on Saturday for a mulligan of sorts to fix what he felt was a triple larceny perpetrated by the three men with the closest view of the action. He'll also get one final chance to restore an aura of invincibility that was cultivated through one crushing defeat after another.