After high expectations surrounded Torres following his £50 million move to Stamford Bridge, the Spaniard has failed to find the net in seven appearances.
Lucas, however, believes the former Liverpool ace will soon regain the form displayed at his previous club.
"We know it was a big change for him," Lucas told the Daily Mirror.
"He did really well for Liverpool and scored a lot of goals.
"I think as soon as he scores the first goal he will shine, the same as he did at Liverpool."
Lucas has tipped Andy Carroll to fill the void left by Torres and the midfielder insists the 22-year-old has the ability to shine on the international stage too.
"We know he has been out for a few months but we already know from the last few games he could play really well," he said.
"Now he is getting his fitness back he will shine for England, I am sure."
Lucas has also been highly impressed by fellow Brazilian countrymen David Luiz and Ramires in their debut term in English football.
"I've known David since I was maybe 19. We used to play for the Under-20s together," he said. "I am not surprised [with his impact]," said Lucas.
"I am really, really happy with the way he has arrived, because I know how difficult it is to adapt in the Premier League.
"He is already scoring a lot of goals and maybe people were not expecting this. And they have been important goals as well so I am happy with the way he is playing.
"Ramires is also doing really well and we are happy because I know how difficult it is for a Brazilian player to come to the Premier League and do well.
"Hopefully more Brazilians will come and help teams in the Premier League."
Lucas is also hoping to be in the Brazil squad to face Scotland at the Emirates Stadium on Sunday.
"The new manager is trying to give opportunities to the young players and trying to build a new team so a lot of new faces are here.
"But we just have to take the opportunity to try and be in the squad all the time and look to the Copa America."