Luiz's future at Stamford Bridge seemed uncertain after he made only nine Premier League starts for the club last season, but he has since established himself as a key member of new manager Maurizio Sarri's starting lineup.
The 27-year-old forward was at his most effective on Saturday, scoring three times in a come-from-behind 4-1 win over an outclassed Cardiff City. "At the moment, in my opinion, Liverpool and Man city are better than us".
While the Premier League only dates back to 1992-93, it requires a long trek through history to find the last time any English top-flight duo managed it.
Manchester United and Arsenal stay six points off the top after 2-1 wins at Watford and Newcastle respectively.
The 94-cap playmaker already has five goals in as many league games this season, and appears to only have eyes for more. "I am not able to think about this as a job, like work".
Sarri has been impressed with the Brazilian defender, as he said: "David has a big future here - he will be very useful for us".
"I thought Hazard was one of the best players in Europe, but now I am changing my mind that he is the best", Sarri said at his postmatch news conference.
"I think in this moment, we are very risky in the offensive phase but we are not so solid as I want in the defensive phase", Sarri said.
There's a busy spell ahead for Chelsea, which includes their first Europa League games of the campaign and two ties with Liverpool, and so both are likely to see some minutes even if Giroud might have assisted his way to the front of the pecking order. So I know that the matches after the break are very, very hard.
Two goals in three first-half minutes from Romelu Lukaku and Chris Smalling put the visitors in command.