Dan Carter says South African loose forward Schalk Burger was the "toughest-minded" player he's ever faced.
Speaking to Newstalk ZB's Simon Barnett and Phil Gifford, Carter said his former Springbok rival was not only tough, but a "top bloke off the field" as well.
"He was tough," Carter said. "I kept looking at my All Black jersey wondering if I had a target like in the middle of the jersey or something because he kept coming for me.
"He was having a huge battle with our big forward pack. He just kept going. He didn't stop. He was physical and just his leg drive was incredible.
"A real competitor and absolute top bloke off the field as well. His mindset was a little bit different when he was out there competing. That just made him such a tough opponent to come up against."
The 38-year-old made his return to New Zealand Rugby with the Blues, but didn't get any playing time during the Super Rugby Aotearoa.
Part of that was probably due to bad luck, with the return of Covid-19 in the Auckland community forcing the clash between the Blues and Crusaders at Eden Park to be cancelled, which Carter was likely to feature in.
Blues coach Leon MacDonald recently indicated that the former All Blacks first-five was ready and willing to play in the highly-anticipated clash before it was canned.
"The fans would have loved to have seen him play in New Zealand again," MacDonald said. "He looked really good but he also offered a lot to us off the park. He was fit and ready to go and a good shot at being there."
Despite not making an impact on the field, Carter's experience and leadership was invaluable, especially in working with Blues captain Patrick Tuipulotu.
"He was Patrick's right-hand man for most of the season and we've all seen him grow as a leader and a player, and Dan is a massive part of that," MacDonald said.
"We know he is a Crusaders man at heart, but to put that aside and join the team is a testament to what a great guy he is."
Carter's future with NZ Rugby is still unknown, with MacDonald saying no serious discussions had been had with the No 10, but he didn't rule out anything developing further after lockdown.