Albion manager Tony Mowbray described the 4-2 defeat by Cardiff City as a "bridge too far" and said it had showed him which players he could trust and which he couldn't to do a job as he attempts to find his defining squad for this season's Coca-Cola Championship campaign.
But Mowbray insisted his players had not let him down despite their capitulation which came during a 30-minute spell in the first half. He said: "The game was effectively lost in that half-hour but the bigger picture is that it gives me some food for thought on one or two players.
"Everyone was given an opportunity to play and it was a learning curve for us. It showed me the players I can trust and the ones I can't.
"You hope to be able to trust them all to do a job but the first half hour was a little bit too much for one or two of them."
He continued: "One or two players might find it a little harder now to get run outs but they need to show a desire to push on and improve their game. We try and work on our game very day but that was pretty raw out there today in front of everyone's eyes.
"I don't like losing football matches and neither do the supporters who pay to come and watch our matches. It was a bridge too far for us and I have to take some responsibility as I made the team changes."