Joseph Parker admits he was made to dig deep for his controversial victory over British veteran Dereck Chisora.
The New Zealand heavyweight survived a knock down inside the first 10 seconds of the first round to come back for a split decision points win in Manchester on Sunday (NZ time).
Parker won the bout on two of the three judges scorecards but Chisora wasn't happy with the result, feeling he did enough with the early knockdown and his activity in the early part of the fight.
Parker felt the result could have gone either way and said he was made to work very hard for victory.
"That was a tough fight.
"I got caught right in the beginning and just had to dig deep and stay focused. Follow the plan that we had in place.
"I sway off it a bit but Derek is a very tough opponent. He came forward and put pressure on me from the beginning and threw big bombs and landed a lot."
In what was a close bout throughout the 12 rounds, Parker proved the stronger of the two fighters in the second half of the contest, doing just enough to notch his fifth straight win.
The former WBO world champion won the fight 116-111 and 115-113 on two of the three judges' scorecards, with the other judge scoring it 115-113 for Chisora.
The result extended the 29-year-old Parker's professional record to 29-2, with his 37-year-old opponent falling to 32-11.
Chisora said he was beyond upset with the judges' decision, adding it was tough to take another close points defeat.
"It's just difficult because I trained hard, I fight, I bring it and put the pressure on, and this is the treatment I get from boxing.
"In my last fight it was the same thing, this fight the same thing.
"They don't like me ... it's just horrible."
Given the close nature of the fight, Parker and new trainer Andy Lee both said they would be happy to give Chisora a rematch.
Parker, meanwhile, acknowledged he still had work to do with his new Irish mentor if he was going to become a two-time world champion.
He and Lee only had seven weeks together to prepare for the fight, teaming up after Parker parted ways with longtime trainer Kevin Barry after an underwhelming win over Junior Fa in February.
Despite having more to improve on, Parker still believed he could reach his goal of winning a heavyweight title for a second time.
"It's very achieveable, I just have to get back to training.
"There's a lot of things I have to work on. I had a good plan in place and, like other fights, I swayed away from it. I have to get back with Andy and work on a few things.
"There's still a lot I can show and just have to keep working on it with Andy. More camps ahead."