The goalkeeper has praised the Scottish champions for their display in Tuesday's Champions League encounter
Goals from Alessandro Matri, Claudio Marchisio and Mirko Vucinic helped the Bianconeri to a comfortable victory, but Buffon has stressed that they cannot afford to take the second leg of the round of 16 tie lightly.
"Celtic are an excellent side and they showed that tonight," Buffon told reporters.
"We're not through yet. It's not good for us to be too relaxed. We must remain focused and keep showing Celtic the respect they deserve.
"We set out to attack them but struggled to get into our rhythm so we had to settle for what we could manage, which was to defend well and break forward on the counter. We did a great job of it too – we were clinical and ruthless.
"We have to be honest though: the game hinged on a couple of decisive moments. But it's a positive sign that things went our way and also that we took our chances."
Juventus resume match action on Saturday when they travel to Roma.