The last time the teams met, Luiz was at fault for the first goal, then gave a penalty and was kicked out as City defeated Mikel Arteta 3-0 at Etihad last month .
The central defender’s calamitous mistakes have drawn much criticism, with many observers pointing out that his career at Emirates could be over as his contract was due to end this summer.
But since then, Arteta has trusted Luiz with a new one-year contract, while the 33-year-old has played every minute of Arsenal’s last five games – three of which were victories.
But city manager Guardiola is not surprised by Luiz’s resurgence, describing the Brazilian as having “an incredible mentality”.
“I have incredible respect for him and for what he has done in his career,” said Guardiola of Luiz at his pre-match press conference.
“He is an exceptional player and he has an incredible mentality and above all a personality.
“I laugh out loud when I hear the experts. Many of them were defenders and they believe that they have made no mistakes in their careers even if they have been playing for 15 or 20 years.
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“I like that Luiz is still playing soccer and I’m sure he’s going to do a lot of good deeds, even more mistakes because it’s part of the game.
“But he does it with dignity. I have great respect for him. ”
City face Arsenal on Saturday night, while Manchester United face Chelsea in the other semi-final on Sunday.
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