"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."
In recent years Daniel Jarque, Antonio Puerta and Marc-Vivien Foe are some of the other footballers to have died from heart problems.