Thomas Muller scored a 90th-minute equaliser to take the tie into extra-time, where Bayern scored twice to prevail 6-4 on aggregate.
"If you want to reach the semi-finals then you have to be ready to beat any opponent," Guardiola said.
"But we are there. We made it. A minute later and we would have been out."
The other seven teams in the quarter-finals are Manchester City, Paris St-Germain, Wolfsburg, Benfica, Atletico Madrid, Real Madrid, and Guardiola's former club Barcelona.
The draw for the quarter-finals takes place on Friday at 11:00 GMT, and the first legs will be played on 5 and 6 April, with the second legs on 12 and 13 April.
Bayern Munich manager Pep Guardiola says he "doesn't care" who they play in the Champions League quarter-finals after beating Juventus.