Arsenal boss Arsene Wenger has paid tribute to Sir Alex Ferguson following news of the Manchester United legend undergoing emergency surgery for a brain haemorrhage.
The 76-year-old was rushed to hospital on Saturday morning to undergo the procedure and is currently recovering.
In a statement, the club said that "the procedure has gone very well but he needs a period of intensive care to optimise his recovery".
Wenger, who enjoyed a fierce rivalry with Ferguson when Arsenal and United regularly fought for the Premier League title between 1996 and 2006, wished his former counterpart a swift recovery.
"I am concerned and I'm thinking about him and his family," Wenger is quoted by the Daily Mail as saying.
"I trust his strength and his strong character will get him well very quickly."
Ferguson was at Old Trafford last Sunday to present Wenger with a commemorative trophy after the announcement that the Frenchman was leaving Arsenal after 22 years.