The Australian Open has been hit by another setback as a fifth person tested positive for coronavirus, forcing 25 more players into hotel quarantine. A total of 72 players are now isolating in their hotel rooms ahead of the tournament. The fifth person tested positive on the night of January 17 and they were on a charter flight from Doha that landed in Melbourne on Saturday. It means three Australian Open charter flights have carried passengers who later tested positive, following infections on planes from Los Angeles and Abu Dhabi. COVID-19 Quarantine Victoria on Sunday said four people in the Australian Open contingent and one airline crew member had now tested positive. Despite some of the affected players complaining of being unable to leave their rooms for training, COVID-19 Quarantine Victoria commissioner Emma Cassar insisted the program would not be modified. Cassar said that there had been cases of “challenging …