Bertrand helped Chelsea win the Champions League in 2012 but is now out on loan with Southampton.
But the left-back is looking ahead not back, with the Saints just four points behind the Premier League leaders.
And although he is still a Blues player, Bertrand is keen that Southampton well against his parent club.
"Of course I have one eye on Chelsea, definitely," he said. "We're trying to catch them at the minute!
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Bertrand wants to catch Chelsea in the Premier League
Of course I have one eye on Chelsea. Definitely. We're trying to catch them at the minute!
Ryan Bertrand
"I tune in and we're winning and they're winning so that's happy days for me.
"I'm just enjoying playing football at the moment so at the end of the season we'll see where I'm best suited playing football on a regular basis."
Bertrand has settled into life at Southampton quickly since joining Ronald Koeman's men in the summer.
And he is full of praise for his new manager, comparing his management qualities to Chelsea boss Jose Mourinho.
"Obviously they are both fantastic managers," he added.
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Bertrand spent last season on loan at Aston Villa
"Koeman has been fantastic for me since I've been there, he's a really humble person who has had a fantastic career on and off the field and I'm relishing the chance to play under him and learn from him.
"It's been good, very easy to settle in, it's a real family club. That's one aspect that it's got and you can really feel that from the moment you step in there. It's been a pleasure."
But where can the road lead to for Southampton this season?
"Who knows?" Bertrand replied. "It's been a crazy league so far, the big teams at the top have dropped points and there's been other teams who have been really consistent, not just us.
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"West Ham and Swansea have started really well so it will be a really interesting season.
"We are fulfilling more than our expectations. But at the same time I think we fully deserve to be there.
The 25-year-old reveals the squad are thinking about a top-four finish – with Saints currently sitting in second – but believes January is a better time for assessment.
"At the moment I wouldn't say so [top-four is out of reach] but at the same time we're aware that it's still early days," he said. "I think we will be able to tell more come January time."
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Bertrand has his eye on full England honours
Bertrand is also keen to break into Roy Hodgson's England squad.
"Of course, that's something I want to progress to and play in," he added.
"That's something I want to do but like I said it's just about playing consistently now. Hopefully my performances are good enough to get recognised."
Ryan Bertrand was speaking at the launch of Call of Duty: Advanced Warfare. To celebrate the early availability of the game, Call of Duty hosted an extra special livestream where the public were able to be part of a celebrity team. Call of Duty is out now on all major consoles - www.callofduty.com
