Palace were impressive for their 3-1 win, with Ismaila Sarr scoring twice for the visitors.
Glasner said afterwards: "We always were dangerous, we took our chances today and it is great win for us and our fans.
"They wanted to win and they showed it from the first second. It took us a little bit but we had more situations in their half and it gave the players more confidence.
"The problem early in the second half was we didn't get pressure on the ball. They have a lot of quality and their subs did fantastic.
"We look up, in front of us, and it was a massive chance for us to reduce the gap to the teams in front of us. But we don't talk about the table, we talk about our performance. The positive thing is we can play better.
"It's a very important game for us, it's a very important game for our fans and I told the players it was the best Christmas gift we could give them because they are always behind us."