WBO light heavyweight champion Sergey Kovalev believes that he's a much different fighter from that man who suffered back to back defeats to Andre Ward.

The first bout, which took place in November of 2016, saw Kovalev lose a close twelve round unanimous decision to Ward. The rematch, which took place in June of 2017, saw Ward stop Kovalev.

As he approached the rematch, BoxingScene.com detailed numerous accounts of the internal turmoil between Kovalev and his former trainer, John David Jackson.

After suffering the second loss to Ward, Kovalev parted ways with Jackson and linked up with veteran trainer Abror Tursunpulatov.

His third fight with the new coach takes place on Saturday night, when he faces his toughest opponent since the losses to Ward. In the other corner will be undefeated contender Eleider Alvarez.

Kovalev explained that Jackson barely helped him in the training camps for the two Ward bouts.

"When I came to America, I came with all my amateur baggage. When I lost twice, I lost because of that amateur baggage and because of my coach. He was my coach but he didn't really work with me. He was like a passenger in the car and I was driving. Now I'm the passenger and my coach is the driver," Kovalev told ESPN.

"I thank God for my two fights against Andre Ward. It changed something inside of me and around me. I changed my team and my coach.

"The next day after the second fight against Ward, I knew I had to change my coach. My coach didn't help me. I'm a different fighter than I was then. The fight would be different if it happened today. The second fight, I was mentally broke. I wasn't ready for the second fight. I didn't train for four months after the first fight, and I didn't really start to train for the rematch until two months before the fight. I was mentally broken. I wanted to kick his ass after the first loss, but everyone told me I wasn't ready for the rematch and when it came time to get ready for the rematch, I felt alone and I was killed mentally."