Spurs have established themselves as the sole challengers to Chelsea for the Premier League title this season, cutting the gap at the top of the table from 10 points to four points since the beginning of April.
The London rivals will switch their attentions to the FA Cup this weekend, but Luiz could not hide his admiration for the opposition ahead of what he expects to be a "fantastic game".
"For me they are an amazing team with an amazing coach in Mauricio Pochettino. They are the best physical team in the League. All 11 players are monsters. I love that team," he told the London Evening Standard.
"It will be a difficult game for us. We need to be ready to play against one of the best sides in this League. But it was always going to be hard when you reach a semi-final. Will we have to be monsters too? Yes. Chelsea also have some monsters and play like a monster like N'Golo Kante. We have different kind of monsters.
"It will be a fantastic game, both clubs are in amazing shape. It will be a top-quality match to watch and you have to play top quality to win."
Luiz has made 28 Premier League starts for Chelsea this season, with his form earning him a place in the PFA team of the year.