Serb Djokovic wrote 'Support Serbia' and 'I love you' on a camera after his 6-7(5) 7-6(4) 6-3 win over big-hitting Canadian Milos Raonic in the Italian Open semi-finals on Saturday, referring to the flooding that has killed at least 11 people in Bosnia and three in Serbia.
"This rain that has been falling constantly for four (days) is going to stop eventually and after that there is a minimum of several months of recovery," Djokovic told reporters.
"People are without homes and need any kind of help."
Over 25,000 people in both countries have been evacuated, while Serbia's energy system was brought close to collapse after days of heavy rainfall, unprecedented since records began almost 120 years ago.
"This is a total catastrophe of biblical proportions. Half of the country is in danger of not having any electricity, we're talking about whole cities, not villages, that are being evacuated," added Djokovic.
"Yes I'm happy that I'm in the final but I'm feeling a bit uncomfortable because there's so many sportsmen back in my country for who everything have been stopped. They're helping and I'm not able to do that."