The world number one was signing autographs after the match when he hurt his leg as local fans pushed towards him.
Leaving his racquets and bag on the court, Djokovic limped straight up the tunnel to receive a medical assessment in the locker room.
The Serbian was unable to complete a television interview he had agreed to after his 6-3 6-4 victory over Seppi that had clinched the match for Serbia.
His on-court performance had been less stressful as he defeated a plucky opponent who pushed him to the limit in a five-set thriller at the French Open this year.
Djokovic only arrived in Perth from Abu Dhabi late on Sunday night and admitted he was troubled by jet lag.
"I felt this morning that I was dream-walking," he said. "I broke the ice after the first set and started to feel better."
Djokovic and Ana Ivanovic took part in the doubles despite holding an unassailable 2-0 in the tie against the Italian pairing of Seppi and Francesca Schiavone after Ivanovic had begun the day by beating Schiavone 6-0 6-4.
The Italians won the doubles to ensure that they only lost the tie 2-1.
Djokovic is taking part in the round-robin team event to be guaranteed at least three matches in his build-up to the Australian Open starting on January 14.
- Sports & Recreation