Danny Rose equalised from the resulting free-kick which flew over everyone and deceived goalkeeper Matt Ingram.
Morgan put 10-man Wycombe in the lead once more from the penalty spot and they looked like they were heading for a surprise win until James Constable knocked the ball back to Mullins who drilled home a dramatic leveller.
"There's a few gloomy faces in our dressing room but you won't see one from me, I'm not down at all," Wilder said.
"It's a battling point for us. And it's a good start to the season with ten points from four games.
"We conceded at a bad time and I don't feel David (Hunt) really needs to dangle a leg out the way he did, but Dean's a clever player and if he's given that invitation, he's going to take it. And he struck the penalty very confidently.
"That goal gave them a lift. It disappointed me because we were massively on the front foot at that point, and there was still half an hour to go."
"At times Wycombe were a touch sharper than us and we didn't move them around enough when they had 10 men, or play with a quick enough tempo, but this game showed my team plays to the end. It might be a valuable goal come the end of the season.
"And yes, of course, there's relief as well.
"Credit too to Wycombe. They got spanked last week, but they scrapped and battled and gave their manager everything.
Wycombe boss Gareth Ainsworth agreed that his players produced ferocious commitment as they bounced back from a poor showing against Mansfield to show their character with 10 men.
"That was a great point for us," he said. "And it's a great turnaround after Mansfield. You worry after performances like last week but my players were terrific with 10 men for half an hour.
"I'm immensely proud of them, they gave me everything they had.
"I thought there was a foul leading up to the goal at the end and the decision not to give a foul then was very disappointing. My lads are down, but they should be proud.
"It showed me last week against Mansfield was just a blip.
"And Dean Morgan coming back in and scoring two goals, and playing the way he did, shows me he wants to be in the team."
Ainsworth did not want to make a judgement on whether Dunne deserved his red card for what the referee deemed was an elbow in the face of Potter.
"We'll have to look at the DVD of it," he said. "If he did catch him in the face with an elbow, it was an accident in Charles's view.
"The biggest disappointment for me is to lose him now for three games."
- Sports & Recreation
- Charles Dunne
- James Constable