Gennady Golovkin, left, and Canelo Alvarez trade punches during Saturday night’s middleweight title bout in Las Vegas. (Isaac Brekken/Associated Press)

For 12 rounds, drama finally eclipsed controversy, and the two fighters exchanged blow after blow, each man desperate to win on his own terms this time.

One year after fighting to a controversial draw, Canelo Alvarez and Gennady Golovkin were back in the ring for their highly-anticipated rematch, and once again it went to the scorecards — and once again there will be plenty of room for debate.

After an action-packed, evenly-fought bout, Alvarez scored the majority victory, thrilling the 21,965 in attendance and handing Golovkin the first loss of his boxing career.

With the narrow win, Alvarez (50-1-2) is the new unified titleholder, taking ownership of the World Boxing Association and World Boxing Council middleweight championship belts. Golovkin (38-1-1) saw his streak of successful title defenses stopped at 20, leaving him tied with Bernard Hopkins for the middleweight record.

It was a raucous sellout crowd inside T-Mobile Arena, the assembled masses holding their collective breath at times as the fighters exchanged blow after blow. The two have now fought 24 rounds, and many of them were decided by the narrowest of margins. In Saturday’s rematch, judge Glenn Feldman scored the bout even, 114-114, while Dave Moretti and Steve Weisfeld both gave Alvarez the slight edge, 115-113. It’s possible it was even closer than that, a testament to how evenly matched and well-prepared the two fighters were.

“I showed my victory with facts,” Alvarez said. “He was the one who was backing up. I feel satisfied because I gave a great fight. It was a clear victory.”

Golovkin surely didn’t feel the same way. The decision hit him harder than perhaps any punch Saturday night, and he stormed out of the ring back to his locker room while Alvarez celebrated with his entourage.

“We had a great fight, the one we expected the first time around,” said Abel Sanchez, Golovkin’s trainer. “I had it close going into the 12thround. We had good judges who saw it from different angles.”

Sanchez said the bout was close enough that the two should square off a third time, which Alvarez is apparently open to.

“If the people want another round, I’ll do it again,” Alvarez said. “But for right now, I will enjoy time with my family.”

Alvarez was more aggressive than their first meeting, but Golovkin seemed able to execute his game plan, too. Intent on making the judges’ jobs even harder this time around, each fighter consistently had an answer for the other, taking a hit and promptly giving one in return.

In the 12th round, both fighters emptied their respective tanks, launching heavy blows and swinging wildly. Golovkin had blood streaming from his left eye, as both boxers fought as if they desperately needed the final round. In the so-called championship rounds, each showed why he’s worthy of a belt. They both landed big blows and both teetered on their feet, absorbing punishment. Golovkin landed the more dramatic punches late, trying to create some separation and erase any doubt the judges might have had, but Alvarez had been tactical and earned his points all along the way.

While the final three minutes were close, two of the three judges gave the final round to Alvarez, all that was needed to avoid another draw and allow the Mexican fighter to raise his hand at the end of the night.

“I’m not going to say who won tonight because the victory belongs to Canelo according to the judges,” said Golovkin, who required eight stitches to close a cut on his right eye. “I thought it was a very good fight for the fans and very exciting. I thought I fought better than he did.”

Since Floyd Mayweather Jr.’s retirement, boxing has been a sport without a transcendent superstar. In 12 exciting rounds, the 28-year old Alvarez made a compelling case Saturday that despite recent controversies, he’s the most capable torchbearer — not just for the middleweight division but for the entire sport.

Saturday’s victory offered Alvarez some degree of redemption after his reputation suffered months of bruising body shots, mostly by his own doing. Before Saturday’s close decision, he hadn’t posted a win in the ring since May 2017, and his showing in the initial bout against Golovkin did little to appease critics.

Then, the original date for the rematch — May 5 — was scuttled after Alvarez twice tested positive for a banned substance, clenbuterol, during training and was hit with a six-month suspension from the Nevada State Athletic Commission. The extended wait didn’t sit well with Golovkin.

Normally soft-spoken and subdued, the Kazakh fighter began lashing out at Alvarez, upset at the obstacles that needed clearing to make the rematch happen. He repeatedly called Alvarez a liar and a cheat, making no effort to hide the animosity that had built up over time.

The two refused to make eye contact at a news conference last week, and then at Friday’s weigh-in, the fighters had to be separated after Alvarez charged at Golovkin, bumping heads during what was supposed to be a routine photo op.

“I want to punish him,” Golovkin said earlier in the week.

All along, Alvarez maintained that the failed drug tests were the result of contaminated meat he consumed in his native Mexico. Alvarez said the chatter from Golovkin’s camp fueled him in the weeks and months leading up to Saturday’s rematch.

“I’m bothered by all the stupid things they’ve been saying,” Alvarez said earlier in the week. “I don’t know which one to laugh about or get angry about at this point.”

The animosity was on full display, both fighters finally given an outlet for pent-up frustrations. Each was measured following the opening bell, with Alvarez controlling the center of the ring and Golovkin testing his jab. Unlike last time, Golovkin did a better job of establishing his jab early, chipping away at Alvarez. The Mexican fighter kept the action in the center of the ring, and by the middle rounds, both fighters were mixing it up and starting to do damage.

For Golovkin, Saturday was supposed to fill a huge hole on his stellar fight resume. He’d whipped every other foe soundly but had yet to notch a signature win, the kind that would help cement his place among the division’s all-time greats. At 36, time was running out. To be mentioned among the iconic middleweights — the likes of Sugar Ray Robinson, Marvin Hagler, Carlos Monzon, among others — he needed to show that he could beat the best.

He has now failed in two opportunities to score a win over Alvarez. The two squared off on Sept. 16, 2017, and while many fight fans believed Golovkin pulled out a narrow victory in that initial meeting, the judges weren’t as sure. One of the three gave Alvarez the edge — an inexplicable 118-110 scorecard — and the fight world clamored immediately for a rematch.

As close as Saturday’s bout was, it’s likely the boxing world will hungrily demand the two meet in the ring one more time.