LAS VEGAS — When Russian prospect Sergey Kovalev first met his future manager Egis Klimas, the boxer wanted to know how much he was going to be paid per fight. This was 2009, and Kovalev and Klimas were both virtual unknowns.

“I asked him, ‘How much will you pay me each fight?’ ” Kovalev said Thursday recalling that first meeting in Kazakhstan. “He said, ‘Nothing. But I will give you food, a place to train and help you find a promoter.’ ”

Klimas also told him, “If you make the American audience like you, then you’re going to have success.”

Klimas and Kovalev gambled on each other and, with their promotional partner Main Events, have reached the biggest night of their careers when Kovalev defends his light heavyweight titles against unbeaten Andre Ward on Saturday night at T-Mobile Arena. HBO pay-per-view will televise ($54.95) only the third meeting ever between unbeaten fighters who rank in the top five of Ring magazine’s pound-for-pound list. The other two fights were Meldrick Taylor against Julio Cesar Chavez (1994) and Oscar De La Hoya versus Felix Trinidad (1999).

Ward is America’s last Olympic boxing champion, having won gold in Athens in 2004. Stardom was predicted. Kovalev, meanwhile, has built his career from scratch, moving to America, partnering with veteran trainer Don Turner before John David Jackson took over in 2012.

Kovalev (30-0-1, 26 KOs) has captivated the boxing public with his knockout power, living up to his nickname “Krusher” and defeating former champions Jean Pascal, Bernard Hopkins and Nathan Cleverly. But Ward (30-0, 15 KOs) is by far his biggest obstacle, an Olympic champion, who has moved up to light heavyweight after cleaning out the 168-pound division. For Kovalev, it’s a dream come true to be headlining in such a big fight.

“After 15 or 16 fights, I had no money, no promoter and not really any future in boxing,” Kovalev recalled. “When I fought in Russia in 2011, I stayed in Russia for two, three months and I almost decided not to go back to America because we didn’t have any plans. Then Egis called me in Russia and said to me that one promoter, Main Events, Kathy Duva wants to give me an opportunity to prove myself.”

He has done that over and over again with an aggressive crowd-pleasing style that has won over plenty of American fans. Ward’s manager, James Prince, characterized Saturday’s bout as Russia versus the United States of America. “The best of Russia can’t beat the best of the United States of America at nothing,” Prince said.

But Kovalev is more emblematic of the American dream, coming to this country with nothing but will and work ethic and capturing the WBO, WBA and IBF titles.

“It was the goal of my life to [accomplish] what I started to do,” Kovalev said. “It was not easy. I was ready to leave boxing, but God gave to us Main Events and Kathy Duva and I showed I deserved to be a professional boxer.”

Saturday night he has to prove he belongs in the same ring with Ward, who is also making his debut in a mega pay-per-view bout.

“This fight is an opportunity for both of us to show the boxing world who is the best pound for pound,” Kovalev said. “I’m sure he will be there to do everything he can to get the victory over me and it’s the same for me. It’s going to be a war between us to see who is the best boxer, and who is the best athlete.”

Ward is known to lull his opponents into fighting his rugged, mauling style. Kovalev needs space to punch.

“I know one thing,” Kovalev said. “I will be ready for anything he has to offer in the ring.”