Spurs made a bright start at Stamford Bridge and saw Harry Kane hit the crossbar in the seventh minute.
They were made to pay for their profligacy, though, as in the space of three first-half minutes Chelsea surged into a 2-0 lead, courtesy of strikes from Eden Hazard and Didier Drogba.
Pochettino acknowledged the result was particularly disappointing, but wanted to focus on the positives.
"[I am] very disappointed with the result, because 3-0 is hard," Pochettino said.
"But we need to take some positives from the team tonight.
"I think that we started very well. We created some chances.
"The first chance they have, they score, and the second, they scored. After, the game changed.
"This, I think, was the difference tonight."
Pochettino - who also felt Tottenham's inexperience hurt them at times - bemoaned his side's failure to score one of their early chances.
"Today, we played good in the start to the game," he added.
"I think we were very brave. And the first chance [for Chelsea], they scored.
"This is football. We need to accept. If you score, the game changes."
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