"The club would like to offer its sincere condolences to the family of the player.
Benitez had recently joined the club from Club America for three seasons.
The player participated for the first time with the team during yesterday's match against Qatar Sports Club in the Sheikh Jassem Cup without complaining of any health problems.
His sudden departure is a big shock for each member of the technical and administrative staff.
He was a player that over the short period he was here was regarded for his high moral character."
More top news
Rains could be heavy at times later in the day.
Police are appealing for witnesses after a suspected flasher was captured on camera by a teenage girl.
A pair of armed robbers who threatened women in their own homes - including a mother and two-year-old child - have been jailed for 40 years.