Dan Carter remains the best fly-half in the world, says Leicester head coach and former team-mate Aaron Mauger.
The pair, who played together for both the Crusaders and New Zealand, will be in opposition in Sunday's European Champions Cup semi-final.
Carter, 34, will line up for French side Racing 92 at the City Ground if he recovers from a leg injury.
"When he's on top of his game, as we saw at the World Cup, there's probably no better," said Mauger.
"He's a fantastic footy player," he told BBC Radio 5 live. "He's pretty resilient, he's always worked very hard to be the best that he can be and that's why he has been one of the best the game has ever seen.
"He's a pretty complete footballer, but we'll be looking to test those skills this weekend."
Mauger feels Carter's game has developed over the past decade, due in part to a run of injuries that left him questioning his future in the sport.
However, Carter returned to spearhead the All Blacks to a second successive World Cup victory last autumn.
"Like any player, he's evolved," added former centre Mauger. "He's had to re-package himself over the years, especially with injuries, but I think he's come back a better player.
"I know the All Blacks have put a lot of time into keeping him in the game, because there were some dark times when he was thinking about throwing it in."
Mauger and Carter leave home
Carter retired from international rugby following last year's World Cup win and moved to Paris for a fresh playing challenge.
Mauger departed New Zealand too, leaving his role as an assistant coach at the Crusaders last summer to return to the Tigers, where he spent three seasons as a player from 2007 to 2010.
"That's the beauty of our game," Mauger said. "Rugby gives us the opportunity to get around the world and try and test ourselves in different environments.
"You probably wouldn't have picked it 10 years ago when we were playing for the Crusaders and the All Blacks.
"But it shows how small the rugby world is. An opportunity comes, you take it, and here we are."
Tigers hunt European glory
But after topping their pool and thrashing Stade Francais in the quarter-finals, Mauger feels reaching the Champions Cup final at the Grand Stade de Lyon on 14 May is overdue.
"There has been a massive amount of growth in our game to get where we are now," added Mauger. "We are pretty well placed to go out and perform on Sunday.
"We are in a space now where our skill-sets have grown, our decision-making on the field has grown, and we have a group who are confident in what we are doing, which is exciting."
Hear more from Aaron Mauger on 5 live Rugby on Thursday from 20.30 BST. England head coach Eddie Jones will also be one of the studio guests.