Djokovic survives scare as rain causes chaos at Australian Open

MELBOURNE -- Novak Djokovic survived a scare to join Roger Federer and Serena Williams in the Australian Open second round as heavy downpours caused chaos on Monday, forcing organizers to postpone a swathe of matches.

Defending champion Djokovic was made to sweat before beating Germany's JanLennard Struff in four sets on the first day, when fears over air pollution were replaced by disruption caused by rain.

While play continued at the three stadiums with retractable roofs, half of the 64 scheduled matches were postponed, ensuring a big backlog for Tuesday.

Wet conditions are unusual for the Australian Open, which is more used to extreme heat and was plagued by smog from bushfires during qualifying, when players suffered coughing fits and breathing problems.

Air quality was rated 'good' as the first round started on Monday but about four hours later play was suspended on outside courts when the heavens opened in Melbourne.

World number three Federer was briefly hauled off court while the roof was closed on Rod Laver Arena before returning to complete a routine 6-3, 6-2, 6-2 victory over American Steve Johnson.

Williams, on the hunt for a record-equaling 24th Grand Slam title, won the first set against Anastasia Potapova in just 19 minutes as she cruised to a 6-0, 6-3 win in less than an hour.