England international Cole put an end to speculation over his future yesterday afternoon by signing a new one-year contract at Stamford Bridge.
However, rather than seeing Bertrand as a rival over the coming months, Cole has insisted that he is happy to act as a mentor to the 23-year-old.
"I didn't just sign because I wanted to play. There is a great player in Ryan and hopefully I can help him. If he gets more starts it will be good for the club to have two left-backs here," he told the club's official website. "I think [having experienced players around the young players] helps. I like to think I have helped Ryan in more ways than one.
"He deserves to be at a big club, he has improved a lot in the few years I've seen him and this year and next year is a chance for him to start more games. If I can stay here and help, it's good enough for me."
Cole has made 32 appearances so far this season, while his understudy Bertrand has featured on 21 occasions.