Both were prominent in the early stages when the Seagulls' smart play indicated a hard afternoon for the home club.
Ward, signed a couple of days ago from Wolves on a season's loan, was involved in setting up several promising attacks which put Birmingham's reconstructed defence under pressure.
But Agustien was the player who created the breakthrough in the 73rd minute. He put a pass into the path of Crofts who scored with a low measured cross shot to the right of Randolph.
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Wednesday morning's weather for the east of the region
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War medals belonging to the late Great Escaper Bernard Jordan will be auctioned for charity.