Bayern won 4-3 on the night - and the quarterfinal 6-4 on aggregate - with Olise on the scoresheet and being named man-of-the-match afterwards.
The France international later said: "It was a good, back-and-forth match. We knew they would try to come back. At first it was a bit like 'goal, goal, goal'. When it eventually calmed down, we played a bit better in the second half and took our chances.
"We showed good resilience to keep coming back. In the end, it was a result we're happy with. I tried (for my goal) five or six times before and I was getting closer each time. It was nice to score."
Senior teammate Joshua Kimmich also said: "We knew that both teams can hurt each other: Bayern with the high pressing, Real Madrid through quick transitions.
"We got off to a bad start, and then conceded again through a free-kick and a counter. The first half was hectic. The second half was calmer; we had more control and then managed to win it in the end."