Jack Ross had high praise for young full-back Denver Hume after his superb showing against Stoke City U21's.
The Black Cats boss struggled to hide his frustration, however, after the farcical confusion over midfielder Max Power.
Power was suspended for the game, from which Sunderland take two points after a penalty win, but the match will not count towards his three-game ban.
Ross called the decision 'nonsensical' earlier on Tuesday.
"I’ve got to choose my words carefully," he said.
"I’ve said prior to the game that this competition, there’s a lot of criteria you have to fill when it comes to picking your team.
"You also get dragged to meetings to make sure you promote the competition and take it seriously, then you get the nonsense earlier on today. It makes it difficult as a manager.
"However, you could see by our selection that we were taking the game seriously. First half we were poor, to be honest, flat and slow. I was angry at half-time but second half we were better, the tempo was better and we plugged away.
"I was pleased we got the reward at the end, it wasn’t an easy game to play in, there was a really good crowd in with regards to the game itself but within the stadium it obviously has a very different feel.
"With Max it's probably come down to them [FA & EFL] butting heads," he added.
"In terms of the appeal process and the findings, no problem.
"But I will never get my head around him not getting available tonight and I know there are other clubs in the same boat.
"I received a communication not long before kick-off that was attempting to clarify the situation but that was reactive, because there’s been some criticism. It is unfortunate they had not prepared for it. It’s not a massive deal, but Max won’t play until the end of September now, it would have been good for him to play.
"It's an effective four-game ban."
Ross was thrilled with the performance of 22-year-old Hume, who stood out with his attacking intent.
He created the best chance of the game, with Benjamin Kimpioka missing a glorious chance to convert his cross.
Ross said: "I thought he was one of the few in the first half that had a real aggressiveness, and I mean that in the best possible way. I’ve been really pleased with him all the way through pre-season and the season so far, he’s adapted really well to how we train and how we do things.
"I have some sympathy for him because he keeps having to play on his wrong side, but hopefully that shows I trust him and for him moving forward, it’ll stand him in really good stead. When he gets to plays on his strong side he will flourish."