Dario Vidosic said his young Albion side had to learn after being âspooked by the scorelineâ at Manchester City.
The head coach was delighted with a first-half display which saw Fran Kirbyâs strike take the visitors into the break with an advantage in Friday's WSL encounter.
But Manchester City regrouped after the interval and ran out 2-1 winners thanks to goals from Bunny Shaw and Yui Hasegawa.
Albionâs coach said: âI think for the first 45 minutes it was really, really good. We created enough but we were not deadly when we created these opportunities. We made the incorrect decision on a pass a few times.
âBut in the second half we were nowhere near it, unfortunately. Maybe the scoreline spooked us. We were 1-0 up, and itâs just the mentality. At times, it looked like an immature performance.â
Kiko Seike has her eyes firmly on the ball in the second half. đˇ Kyle Hemsley.
Kirby was withdrawn at the interval, and the head coach admitted her absence may have affected the outcome.
He added: âLosing Fran wasnât ideal. Sheâs our leader on that pitch. In the first half she gave us a lot. She was picking up good spaces through her intelligence.
âSheâs been there. She understands it. She helps and I think we lacked that a little bit in the second half. But weâre a young team and we need experience. We still have a lot of girls who are getting their first minutes for a long time.
âThere are positives. But we have to improve and we have to improve quickly.â
Albionâs fans made themselves heard in the Joie Stadium throughout the evening and the head coach wanted to thank them personally.
He added: âItâs a very long trip. We are very thankful for their support. They wanted to help us and they did help us, but unfortunately it wasnât enough to get us the result.â