Glasner felt that his team had done enough to win the game on Saturday.
"There's a little bit more disappointment about the result," Glasner admitted. "But I think, especially at the end, we deserved to win the game.
Sunderland's goalkeeper made several impressive saves, including three or four incredible stops.
Palace missed some chances to score, and if they hadn't taken them, it was crucial not to concede.
Glasner praised his team's defensive consistency, saying they controlled the game well and only gave Sunderland one chance in the first half.
Tyrick Mitchell made an exceptional block, and the team's overall defensive performance was strong.
However, in terms of scoring goals, Palace didn't have their best performance in terms of efficiency.
Despite this, the team remained unbeaten, and Glasner was optimistic about the result.