SYDNEY, Jan 6 (Reuters) - Australian Prime Minister Scott Morrison on Thursday said "no one is above rules" after the country"s border force cancelled the visa of Novak Djokovic and denied him entry into the country to play in the Australian Open tennis tournament. "Djokovic"s visa has been cancelled. Rules are rules, especially when it comes to our borders. No one is above these rules," Morrison said in a tweet. Djokovic, the world number one tennis player, was initially granted a medical exemption from the country"s COVID-19 vaccination requirements to play in the Australian Open but he was left stranded at Melbourne airport overnight over visa issues. read more