Inter's side had a combined age of 347 and an average age of 31.54, with the five-man defence, including goalkeeper Luca Castellazzi, clocking up 171.
Ranieri said it was the right way to get Inter out of their current predicament where they are 17th in Serie A with only two wins in nine outings.
"You can't underestimate the value of experience, think of it as an old guard," the former Chelsea, Juventus and AS Roma coach told reporters at the San Siro.
"The team is compact, it is determined. I have faith in them, because it is a moment of great difficulty and pressure. It wouldn't be easy to put young lads in there at this stage.
"They are used to big matches and to being under pressure. That doesn't mean to say that when the moment is right, I won't give a chance to one of the other younger players," added Ranieri, who brought on 23-year-old Argentine Ricardo Alvarez in the second half.
Captain Javier Zanetti, the oldest player on the pitch at 38, was making his 93rd Champions League appearance with 33-year-old Dejan Stankovic making his 84th and defender Lucio, 33, his 78th.
Eight of Inter's starting line-up were over 30.
Inter's Champions League form, where the 2010 winners are top of their group with nine points out of 12 and close to reaching the last 16, has been a welcome contrast to their Serie A performances.
"In the Champions League, we have had that bit of luck that we have been lacking in Serie A," said Ranieri.
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