AmaTuks were beaten 2-1 after extra-time following their 1-1 draw during regulation time, with Mozambican international Elias Pelembe scoring a stunner in the 97th minute to eliminate Barker’s side.
"We started the game poorly and we showed Sundowns too much respect," said Barker after the match.
"We allowed them too much space. They dictated the pace of the game, they passed the ball well and we were off the pace.
"By saying that, in the first half we created 2 really decent chances that we didn't take, and we conceded," he added.
AmaTuks went into the half-time break trailing by 1-0, but came back guns blazing in the second half, to get an equalizer through Ugandan striker Geoffrey Massa in the 72nd minute.
"At half-time I chatted with the players and told them that we need to show more courage, we need to show bravery, boss both our defence, and attack.
"I think in the second half we were a much better team. We put them under a little more pressure, tried to squeeze them a little bit and started getting control of the game in parts of the second half, which led to the equalizer, which was a deserved one," conceded Barker.
"We went to extra-time and thought we were still in it. But at the end of the day, the difference between the two teams came down to individuals, and quality of players that can create moments that can get winners.
“Unfortunately we don't have as many as Sundowns, and I think that was the difference at the end of the match,” concluded Barker.