The Brazil international completed a surprise £32m move to Chelsea from Ligue 1 side Paris Saint-Germain on transfer deadline day.
Antonio Conte’s decision to sign the previously erratic South American was questioned following Luiz’s inconsistent performances during his first spell at Stamford Bridge.
Chelsea lost 2-1 to top-four rivals Liverpool before a 3-0 defeat by London neighbours Arsenal in Luiz’s first two starts following his big-money return to west London.
However, the Blues have managed to keep back-to-back clean sheets in victories over Hull City and Leicester City to get their Premier League back on track.
Former Tottenham forward Crooks says he has been impressed with Luiz’s performances in Conte’s back three since the Italian’s tactical switch at the west London club.
“I have been very critical of Luiz in the past, but I must say his time at Paris St-Germain has proved profitable for Chelsea,” Crooks told BBC Sport.
“Since the Brazilian’s return to Stamford Bridge this summer, I have noticed he is a much more mature defender who is far less concerned about what he can do on the ball. These days he concentrates on stopping those with the ball from playing.
“In a back three, which seems to suit Luiz, he dealt with Leicester striker Jamie Vardy comfortably. Keeping clean sheets helps win titles and, while I see Chelsea a little short of that this season, I am starting to appreciate a defensive unit who might start to cope with life at Stamford Bridge without veterans John Terry or Branislav Ivanovic. It’s about time.”
Luiz moved to Ligue 1 champions PSG in a £50m deal from Chelsea in 2014 after the Brazilian was deemed surplus to requirements at Stamford Bridge.
Chelsea will host Manchester United in their next Premier League game at Stamford Bridge on Saturday evening.
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