The Bolton boss admitted his side were second best in South Wales, as goals from Omari Kellyman and Chris Willock sealed a comfortable win for the Championship-bound Bluebirds.
Wanderers did not manage a shot on goal for more than an hour and, Schumacher admitted, seemed to struggle with confidence on the ball all afternoon.
“We were comprehensively beaten by the best team,” he said. “They started the game much brighter than us.
“We said before the game that we'd have to have the best version of ourselves to get a result down here, and I don't think we got that today.
“I thought we lacked any sort of belief, certainly in the first 45 minutes, we just didn't have any courage to take the ball. I think part of that is down to a good press from Cardiff but when we did have any sort of spells in the final 30, we had no energy, no belief and no spark.
“They were far better than us in all departments, so they deserved to win.”
Plymouth’s draw against Exeter means that the gap to seventh spot is seven points with four games to go. Bolton are yet to confirm their place in the play-offs and Schumacher admits the performance against Cardiff is a worry.
“The performance is a concern because we knew we had to get to a certain level today to try and get anything from the game, and we didn't. We didn't get to that level,” he said.
“I said to them at half-time that we're still in the game, we've conceded too many shots, but we're still in it. What are we waiting for? Take the handbrake off?
“Are we waiting for them to score and for us to start moving and passing the ball? I said, come on, we've got nothing to lose, let's go for it. To be honest, their individuals today were miles better than ours.
“The way they played and the way they passed, they played with confidence and we never did. The last 20 minutes, we had a little bit of a go when the game sort of opened up a little bit, but apart from that, I say we didn't deserve anything from it.”
Wanderers face Stevenage on Tuesday night – a small solace for Schumacher, who feels his side will be keen to produce a response.
“Sometimes you get a bad day,” he said. “Not too many times this season I've come away from a game and said we were well beaten in all departments. I think Peterborough away was the only other time I've actually said that.
“Two times in 42 games, that's happened. But I don't know, we're a bit short, as you know, the squad. The two midfield players have been a big miss, having them and people like that in there in that type of game where you've got to be really aggressive and turn the ball over, they've been a miss.
“But I think today when we did turn the ball over, certainly in the first half, Kellyman lost it twice right in the centre of the pitch. What we've worked on and what we were so effective at in the first game against these is counter-attacking from that. We were rubbish with it, we kept giving them the ball straight back.”
