A 19-year-old is currently in police custody.
Officers are appealing for witnesses to an assault that happened in Thurmaston in the early hours of Sunday morning.
At 00.33 am police were alerted to reports of a man on the ground with a head injury.
Reports from people at the scene suggested the 24-year-old man had been hit, and fell to the ground.
DS Charlie Massarella, said: “We know there had been a significant gathering at a premise in Melton Road, close to the White Hart Close turning, earlier in the evening.
“We have spoken to a number of people who were there, but we need to speak to anyone who has any information about what came before this incident. What happened that led to a fight breaking out? Who was there? Who is responsible?
“We need to hear from you.”
The victim was taken to Queen’s Medical Centre in Nottingham where he remains in a critical but stable condition.
A 19-year-old man, from Leicester, has been arrested on suspicion of grievous bodily harm (GBH) and is currently in police custody.
Anyone with information is urged to contact the force, calling 101 and quoting incident number 21 of 10 April.
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