The defender has come in for some criticism recently from supporters and pundits.
However, left back Tierney believes Luiz is a leader and someone who acts as inspiration to the club's younger players.
"He's a legend. The biggest legend ever. He's so good with all the young boys. Everybody loves him. He's a proper leader. If he's not got the armband, he still leads," Tierney told Open Goal.
It would appear Luiz is well liked in the dressing room, and it may be the reason why he earned a new contract from manager Mikel Arteta.
The club are targeting centre-backs his window, which means Luiz is likely to be a rotation option next term.