The 22-year-old made his Blues debut in April 2011, six years after joining the club from Gillingham, and after graduating from the club's youth system, Bertrand is now tipped for a bright future in west London.
After an unsuccessful attempt to sign Pereira in the summer - a move that would have seen the Uruguayan international defender follow in the footsteps of Chelsea manager Andre Villas-Boas - who arrived at Stamford Bridge in June, the Blues boss has now made clear his intentions to give Bertrand a chance to make the position his own.
"We decided not to [bid for Pereira again], based on prices and because we are not looking," said Villas-Boas. "We are pretty satisfied with what we've got.
"Ryan Bertrand has shown fantastically good levels of understanding and talent at left-back and Ashley Cole is continuing to perform fantastically well too."
Having featured for Chelsea in the Carling Cup this season, Bertrand has convinced Villas-Boas he has what it takes to succeed at the top level.
In the short-term he will continue as understudy to England international defender Cole, but is widely regarded as Stamford Bridge's long-term left-back successor.