Ryan Mason revealed it "hurt" to watch his players perform valiantly in the second period after seeing them produce a below-par display in the first 45 minutes at Southampton.
The Baggies found themselves 3-0 down at the break at St Mary’s Stadium following Leo Scienza’s strike and Adam Armstrong’s brace.
Efforts from Karlan Grant and Nat Phillips ensured an exciting finish on the south coast, but Mason’s men were unable to force an equaliser despite creating opportunities to grab it.
The boss accepted his team gave themselves far too much work to do after the interval and admitted the opening 45 was "unacceptable".
Ryan said: “It wasn’t good enough tonight. We’ve lost another game of football away from home.
“There’s a certain level of expectation and demand when you represent this football club and, at the moment, me and us as a group aren’t reaching that away from home.
“To lose the amount of games we’ve lost away from home is well below the standard that we’re trying to set, as well as the expectation. It’s bitterly disappointing.
“I hated the first half. We’ve gifted Southampton goals. The second half is a different story, but that’s irrelevant to me because I know what this group can do, I know the quality we have and my belief in them is so high, but, the first half is unacceptable in many different ways.
“It needs to be fixed. We need to try and fix it as quickly as possible because to lose the amount of games away from home as we have is far, far, far from acceptable.
“I think there was potentially a lack of belief. That’s my feeling. Maybe I’m wrong. I guess it’s my job to transfer that belief to the group. We can give information and let them know about situations that are going to play out in a game, but it’s my job to transfer that belief into the players.
“The three goals we conceded in the first half were so frustrating. We had moments where we played it right and there was no danger. I can’t make excuses. It’s still so fresh and it’s hurting so much. It’s tough to analyse.
“We were well off it in the first half. In terms of things like belief, quality and humbleness to suffer in certain moments, we didn’t quite have that ability. To concede three goals in the way we did and give the opposition a three-goal head start is extremely difficult to come back from.
“We could have left here with something to show, but we didn’t. I can’t look too much at that. Trust me, it hurts me more seeing the second-half performance because I have so much belief in this group and in the individuals.
“We’ve had a lot of hurdles and challenges. We’ve come through some of them and some of them we haven’t. It hurts me to see the second half and how good we were, but a game of football isn’t 45 minutes, it’s 95/100 minutes.
“We’ve gifted the opposition goals and made it extremely difficult for ourselves. We showed fight, personality and quality in the second half, but that’s irrelevant to me at the moment because the first half is the only thing I’m thinking about.”
