Flash back to late 2016 and Sergey Kovalev was on top of the mountain. The man known as "Krusher" owned three light heavyweight world title belts and an undefeated record. He was near the top of most pound-for-pound lists, was knocking almost everyone out and carried an aura of invincibility.

Sergey Kovalev vs. Vyacheslav Shabranskyy Where: The Theater at Madison Square Garden, New York

When: Saturday

TV: HBO (10 p.m. ET/PT)

Now, one year later, Kovalev is in a much different place.

He is coming off two losses in a row to now-retired Andre Ward, though the first fight, last November, went to Ward by a highly disputed decision in a fight most thought Kovalev had won. But Ward left little doubt in an eighth-round knockout in the June rematch.

Gone are Kovalev's title belts and his perfect record. The notion of invincibility is also long gone, and now he starts anew.

"We're having fun now. It's a job, but it's always better when you can enjoy your work," said Main Events CEO Kathy Duva, Kovalev's promoter. "Sergey's made it very clear that this was all a wake-up call for him. He's decided to get it together. You can't be the champion of the world and out with your friends.

"The day he [unified titles against] Bernard Hopkins [in 2014], Bernard told Sergey, 'You're going to be a champion as long as you want to be. As long as you keep focus, nobody's ever going to beat you. You're going to lose when you lose focus.' He's got a chance now to hit the reset button."

Kovalev, who spent time at a monastery in Greece to clear his head and prepare mentally and spiritually for return to boxing after the second loss to Ward, claims he has a new attitude.

"All life is like a lesson for me," Kovalev said. "Right now, I feel all bad things are gone from my mind. Right now, I concentrate, and I focus for the future of my boxing career. I'm ready to be a world champion again and collect my belts if somebody will be ready to unify the title."

He has hired a new trainer, Uzbekistan's Abror Tursunpulatov, a complete unknown in this part of the world, after his relationship with longtime trainer John David Jackson was fractured beyond repair by recent tension-filled training camps.

Kovalev, a Russia native fighting out of Los Angeles, also said he has begun to eat better and has stopped drinking and partying. He claims he is now focused on getting the most out of himself.

"We're having fun now. It's a job, but it's always better when you can enjoy your work. Sergey's made it very clear that this was all a wake-up call for him. He's decided to get it together. You can't be the champion of the world and out with your friends" Kathy Duva, Sergey Kovalev's promoter

His performance, of course, will serve as the proof of where he is in a career that begins a new chapter against Vyacheslav "Slava" Shabranskyy for a vacant light heavyweight world title -- one of Kovalev's old belts, which Ward vacated upon his retirement in September -- on Saturday (HBO, 10 p.m. ET/PT) at the Theater at Madison Square Garden in New York.

"Right now, God has blessed me and given me this opportunity to get back to this level," Kovalev said.

Jackson has said it got to a point where Kovalev was essentially training himself as their communication broke down. Kovalev said he believes he now has the right person for his corner, even though he won three belts with Jackson at his side and made eight defenses in dominant fashion.

"I worked hard by myself, but with Abror, these workouts are different dosages, intervals. If today we're working very hard, then next day is a little bit lighter, working on my style," Kovalev said. "When I work myself, I work hard every day. I didn't give a rest to my body, it wasn't good.

"We're just working on my strengths, what I can do the best. We are working on my body, my style, and what I can do much better."

Sergey Kovalev has focused on his training after two consecutive losses and expects to become a world titlist again. Photo provided by Craig Bennett/Main Events

As for his diet, he said the changes are for the better after claiming that he overtrained for the first fight against Ward and had little energy. He said he wasn't himself in the second fight, either, but also complained about low blows being responsible for his loss.

"More natural, more organic [foods]," Kovalev said of his new diet. "I like it. If you cook right, it's very delicious and very healthy. I'm feeling what I'm eating. I am what I'm eating. You are what you eat. Really, I feel this, and my energy is much better with the right food."

And then there is his new trainer. Jackson didn't speak Russian, though Kovalev has good command of English. But Tursunpulatov speaks Russian and Kovalev is more comfortable with it being spoken in camp and in his corner.

"It will be a great fight. Let me show you different boxing, the real Sergey 'Krusher' Kovalev. I've changed a lot of things. I've deleted a lot of mistakes. It's time to change." Sergey Kovalev on his fight against Vyacheslav Shabranskyy

"I'm very glad to work with Abror. We understand each other; we speak the same language. It's the most important thing," Kovalev said. "I understand what he wants. If he says something about an exercise and I don't agree, we discuss it and we find compromise, some solutions. It's almost never happening, because what he's giving me, I understand it can help me.

"We are the same mentally. I understand where we go, for what, and why. I feel very comfortable to work with him and very happy he has control of my training camps and my conditioning for my shape."

Tursunpulatov claims all has gone well in their pairing, which became official only about a month ago. The two had met when Kovalev's promotional company, Krusher Promotions, signed Russian middleweight Bakhram Murtazaliev, who is also trained by Tursunpulatov.

"We come from the same training facility; we have the same manager, Egis Klimas," Tursunpulatov said. "We live there like brothers, and if someone is in a bad situation, someone is hurt, all of us are hurt. I don't have no pressure. Of course, I want to prove he is the best. I can do it, and I feel very comfortable.

Light heavyweight Sergey Kovalev, right, lost two fights in a row against now-retired Andre Ward. Christian Petersen/Getty Images

"The main important thing is for Sergey to work under my supervision, under my plan, and if it works under my plan and my supervision, that is when we are going to get results."

Klimas claims he has seen results quickly in Kovalev's pairing with Tursunpulatov.

"I see a completely different person. He is more concentrated, more focused, more dedicated; he's training hard, he's watching his diet," Klimas said. "He made the big changes in his head. Because of these couple of losses, I can even blame myself for some of it. It was my mistake. I realized he needs to get out of his comfort zone. Everything is for the better."

Kovalev (30-2-1, 26 KOs), 34, figures to look good against one-dimensional Shabranskyy (19-1, 16 KOs), 30, a native of Ukraine who fights out of Los Angeles. He's a good puncher with a big heart but not a lot of skill.

Kovalev can't afford to take him lightly, however, and said he isn't.

"Slava Shabranskyy is a real fighter. The fight is going to be interesting," Kovalev said. "He is ready to fight, and I am ready, too. He is very motivated because it is a title fight. We're both happy and very motivated. It will be a great fight. Let me show you different boxing, the real Sergey 'Krusher' Kovalev. I've changed a lot of things. I've deleted a lot of mistakes. It's time to change."

The tripleheader also features a pair of 10-round fights: