LAS VEGAS -- So much for the lovefest between Canelo Alvarez and Daniel Jacobs.

A promotion that bordered on boring because they were so respectful to each other and spoke about each other in such glowing terms went out the window Friday. Emotions boiled over after they weighed in for their middleweight world title unification fight, which will take place Saturday (DAZN, 9 p.m. ET) at T-Mobile Arena.

After Alvarez weighed in at 159.5 pounds -- a half-pound under the division limit -- and Jacobs weighed in at 160, they strode toward each other for the traditional faceoff, and they immediately put their heads together. When Jacobs tried to push Alvarez's head back with his, Alvarez shoved him, and there was a brief skirmish. They were quickly separated, and the largely pro-Alvarez crowd on Cinco de Mayo weekend cheered wildly.

"I see fear, and that was fear right there what he did," Alvarez said moments later through an interpreter. "For me and my people, my team and for my fans, it's very important [to win]. This is the challenge we have, but I'm ready for it, and we're going to win. I hope he tries [to take my belts], but he won't be able to."

Alvarez shoved Gennady Golovkin in September after they weighed in for their much-anticipated rematch, also at T-Mobile Arena, and the next night, Alvarez won two major world titles by majority decision. That was a rancor-filled buildup, but Alvarez-Jacobs had been entirely different.

After the weigh-in, Jacobs was highly animated and had words for Alvarez.

"Emotions flying high. I ain't never backed down from a challenge in my life," Jacobs said. "I'm from Brownsville [in Brooklyn, New York]. I never did, and I never will.

"Listen, this is the opportunity of a lifetime. I feel like I'm the best middleweight in the world, and that m-----f----- right there, he gonna get it. ... Let's do this Saturday night! Period! Bumping me with that big-ass head, it's time to put on. I'm gonna talk with my fists [on Saturday]."

Even though both fighters made weight, they are subject to a contractual rehydration clause that Alvarez (50-1-2, 34 KOs), 28, of Mexico, demanded because of Jacobs' size advantage. He wanted to assure that Jacobs (35-2, 29 KOs), 32, would not bulk up too much before the fight, and Jacobs agreed to it, admitting that without agreeing he probably would not have gotten the fight.

Alvarez and Jacobs, both of whom will be making their first title defenses, will be subject to a weight check at 8 a.m. PT Saturday, at which neither man can weight more than 170 pounds, 10 over the middleweight limit.

Each man will reweigh in his respective hotel suite with a member of the other camp on hand to observe. If either fighter is more than 170 pounds, he will be fined $250,000 per pound that he is over. If a fighter is, for example, a half-pound over, he will get a $125,000 fine. Should either fighter blow off the weight check, he will be subject to a $1 million fine.

Both should have plenty of cash to cover a possible fine. According to the Nevada State Athletic Commission, Alvarez's purse is $35 million for the second fight of the five-year, 11-fight, $365 million deal he signed with sports streaming service DAZN last fall. Jacobs' official contract purse is $2.5 million, according to the commission, though he is guaranteed more than $10 million under his deal with DAZN.

Vergil Ortiz Jr. (12-0, 12 KOs), 21, of Dallas, one of boxing's best prospects, weighed in at the welterweight limit of 147 pounds for his 10-round co-feature against Mauricio Herrera (24-8, 7 KOs), 38, a former world title challenger from Riverside, California, who was 146.5 pounds.

Junior lightweight Joseph Diaz Jr. (28-1, 14 KOs), 26, of South El Monte, California, a former featherweight world title challenger, was 129.5 pounds, and Nicaraguan southpaw Freddy Fonseca (26-1-1, 17 KOs), 27, was on the division limit of 130 pounds for their title elimination fight.

Junior lightweight Lamont Roach (18-0-1, 7 KOs), 23, of Washington, D.C., was 129.5 pounds, and Jonathan Oquendo (30-5, 19 KOs), 35, of Puerto Rico, was 130 for their 10-round regional title bout.

Former junior middleweight world titleholder Sadam Ali (27-2, 14 KOs), 30, of Brooklyn, New York, was 147 pounds, and Anthony Young (20-2, 7 KOs), 31, of Atlantic City, New Jersey, was 146 for their 10-rounder.

John Ryder (27-4, 15 KOs), 30, of England, was 167.5 pounds, and Bilal Akkawy (20-0-1, 16 KOs), 25, of Australia, was 167.5 for their fight for a vacant interim super middleweight world title bout. Ryder was initially supposed to face former middleweight titlist David Lemieux, who was moving up in weight, but Lemieux dropped out three weeks ago because of a right hand injury.

The commission released the rest of the purse totals. Ortiz and Herrera will each make $75,000, Diaz $100,000, Fonseca $10,000, Roach $75,000, Oquendo $50,000, Ali $150,000, Young $45,000, Ryder $100,000 and Akkawy $30,000.