Jonas Lossl's own goal gave Brighton the lead but Mounie capitalised on a blind backpass from Shane Duffy to level the scores. Davy Propper was sent off in the second half but Huddersfield couldn't take advantage.
"In general I’m happy," said Wagner, quoted by the Huddersfield Examiner. "I’m pleased with the performance and with the response the players showed after a tough 4 or 5 minutes and the goal.
"We created moments and had the possession we wanted to have. Both teams wanted to win and it was a good football match from both teams. We were able to win it with our opportunities, but Brighton had opportunities as well."
Propper was dismissed as he misjudged a dangerous tackle on Jonathan Hogg, who had to be taken off. Wagner made it clear that he was in agreement with referee Anthony Taylor's decision.
"Last week we had a similar tackle which made us lose [Elias] Kachunga for three months," said Wagner. "Today this tackle was too dangerous. You cannot risk your opponent getting an injury.
"Hopefully Jonathan Hogg will not be out as long as Kachunga, but we need to make further assessments."
Huddersfield now have 32 points and are four clear of 18th-placed Southampton, although the Saints do have two games in hand. The Terriers have a very difficult run-in to come, in which they face three of the Premier League's top six.
Their quest for survival continues next week as they host Watford at the John Smith's Stadium.