Beaten 2-1 by Fiorentina on Thursday night, Palace reach the final four 4-2 on aggregate.
Glasner said afterwards: “We expected Fiorentina to try everything and that's what they did.
“It was a great start into the game by us, a big chance after two minutes to take the lead. But then we got a little bit passive, Fiorentina got the penalty, they got the belief back.
“It was very difficult to manage today, not just for me but for the players, making two substitutions before half-time. That means we lost two windows for subs, that's why we took off JP Mateta at half-time – because we knew that he can't play the full game and we needed another window to be flexible in the second half.
“To be honest, their second goal was too early, a great finish from outside the box. But then credit to the players for how they coped with the situation.
“I think we didn't really play well in the attack, but we defended very well. And also we had to make two subs: a very important one central defender in Maxence Lacroix and Adam Wharton, a very important midfielder.
“All the players who came on did so well. As a team I think we defended very well and didn't give them a big chance after they took the lead, and over the two legs I think we deserved to qualify for the semi-finals.”
On Palace's injured pair, Glasner added: “Adam was his adductor, for which he had to leave the England camp. And let's see, he says it doesn't look so serious, but of course, we have to assess him further.
“And Maxence, I think he touched foot to foot and then he felt his knee, I think the medial ligament, so let's see. It's painful."