Spurs lost this preseason friendly 4-0, with Harry Kane scoring and missing from the penalty spot against his old club. Konrad Laimer and teens Lennart Karl and Jonah Kusi-Asare also struck.
"I think we played a very good Bayern team that performed very well tonight," Frank told football.london. "We obviously didn't perform as good, so that was a bad combination, and I think we lacked energy, and we can't play without energy against a team like Bayern.
"I don't think it's because the players didn't want to do it. We've seen it with plenty of energy against Arsenal and Newcastle, for example, especially with the Arsenal performance, which was a good one. So, I think it's definitely a game we'll learn a lot from. It's a team that will compete for the Champions League title that we played today. There's bits we'll definitely learn from this game."
He added: "I think we played a game where there were a lot of factors already, so I think right now we'll watch it back calmly, while not making too many conclusions now. But we learn every every day on the training pitch. Every match we learn. So we definitely learned today. We're not at a top consistency yet. Hopefully that's what we will build towards."