The attack happened on Saturday at around 3.40am at Utopia, Esplanade.
The victim, a 30-year-old man, was talking to a woman in the club when another woman approached him.
After an argument, police said she struck him with a glass.
He suffered a deep cut to his arm following the attack.
A woman, 21, has been bailed pending further inquiries.
Police are now trying to trace two women from Driffield that the man was speaking to prior to the assault.
The women or any other witnesses are asked to call 101, quoting crime reference number 2236362.