NEW DELHI: Australia's Usman Khawaja had a rocky introduction to Brendon McCullum during the 2011 Test series against New Zealand.

"He absolutely tore shreds off me," Khawaja said, as quoted from Fox Cricket.

"He sledged the crap out of me, like I'd never been sledged in international cricket before," the Australia batter added.

By the time Khawaja encountered McCullum again in Test cricket in 2015, the New Zealand star had undergone a remarkable transformation. Now widely recognised as a symbol of sportsmanship, McCullum had even received the ICC Spirit of Cricket Award for leading a New Zealand team renowned for its respect and fairness on the field.

As captain, he had also banned sledging within the Kiwi camp - a decision that former Australian pacer Mitchell Johnson had once mocked.

"It was really bizarre, a few years later when we played against him and he was captain...he was a totally different person," Khawaja said, as quoted from Fox Cricket.

"He was chilled and just went about his business," he noted.

Following Australia's 2016 tour of New Zealand, which was also McCullum's farewell Test series, Khawaja approached him during the post-series drinks. It was there that the former New Zealand captain offered a heartfelt apology for his past verbal jibes.

"I won't say exactly the words that he said, but he was just like, 'Yeah. I was a bit of a...I've learned a lot and matured since then,'" Khawaja recalled.

"But when I was young, he nailed me, so it is funny to see both sides," he added.

"I respect someone who matures and looks back and thinks, 'Yeah, I probably wasn't playing the way I wanted to there.' I have nothing but respect for that," he said.

Later that year, McCullum reflected on his early career in his autobiography, admitting that he was not proud of certain actions. He recalled a 2006 incident in which he ran out Muttiah Muralitharan while the Sri Lankan was celebrating teammate Kumar Sangakkara’s century - an act he said he deeply regretted.

"I wasted a few years trying to be brash and arrogant and hard-minded," McCullum penned.

"It was a false attitude, not true to my character," he added.