The Brazilian returned to Stamford Bridge at the beginning of the season, two years on from leaving for Paris Saint-Germain, prompting many to question the £34 million price tag.
During Luiz's initial three-year stay in the Premier League, Gary Neville once compared the player's defending to that of a 10-year-old controlling a PlayStation game - an assessment which stuck.
Conte notes the poor reviews Luiz previously garnered but was never in doubt over the centre-back's suitability to the cause.
"I read a lot of bad things about him, asking why is he coming back to Chelsea because in the past he performed bad, that he is not a defender, that we had spent a lot of money on him," he told the club's official website.
"I think this was a great challenge for him but also for me, because when you have a player with great ability you can work to try to improve some situations and it is great, you can see for sure that David is a really strong defender.
"I like to repeat to him that it is very important to have the right concentration. His role is a crucial role for us and he has performed very well, but I want him to perform well for the rest of the season.
Conte added: "When we decided to buy him we were sure we were taking a really good player to work with and put as one of the best defenders in Europe.
"This position is perfect for him. He is strong physically and has good technique and can start our possession. He has the personality to do this, and also he has on his flanks two really good defenders."