But admits improvements are needed if Manchester City are to win Europe's elite competition.
Two goals in the final five minutes turned the game around and put City into a commanding position ahead of the second leg at the Etihad in three weeks time.
It was an exciting evening that saw City produce some brilliant football, but Guardiola says his players cannot afford to make mistakes like they did in the VELTINS-Arena if they want to progress in the competition.
“To go away and score three goals, the way we start, the way we finish, the way we react at half time – I am more than delighted," he said.
"But it’s not enough in this competition. We have them first goal, we gave them second and the red card.
"We need to improve. We are a nice team to watch. I don't know how far we can get but we are nice to watch.
"I know because I was living here [in Germany], and i remember as a player, how difficult it is. Always it’s tough. We gave them opportunities be in the game and we have to improve."
After a four-minute delay while officials consulted VAR, a penalty was awarded, which Nabil Bentaleb dispatched emphatically.
But Guardiola refused to complain, instead backing the decision of referee Carlos del Cerro Grande and once again stating his belief that VAR will be good for the integrity of the game.
"It’s a penalty," he said. "VAR last season against Liverpool would change the game for us.
"I am a big fan of VAR.
"It will improve. When a new system starts, it’s like managers. People expect you to win every game 6-0.
"VAR will improve, the machine broke, okay, next time it will be better.
"I support the initiative because I support fair football."