Charleroi, Belgium - World No 1 Novak Djokovic is angry at the state of the court that will be used for this week's Davis Cup first-round tie between Serbia and Belgium.
Djokovic and the rest of his Serbian team are unhappy that a clay surface has been laid on top of a parquet floor.
"This is definitely the worst court we have ever played on," he told a news conference on Thursday. "We're all putting our health at stake here.
"How is it possible that a clay court can be solid and can be a successful, playable court if it's built on parquet? We tried to slide a few times... but our feet stayed under ground."
Djokovic, back in the team for the first time since September 2011, also said he was still feeling jet-lagged after beating Britain's Andy Murray at the Australian Open final on Sunday.
"I am not fully recovered and I'm doing my best in order to prepare myself for tomorrow," he said.
Serbia are without injured world No 9 Janko Tipsarevic but are still favourites to progress against Belgium who are led by world number 50 David Goffin and 127th-ranked Olivier Rochus.
The other singles player for the Serbs is world No 39 Viktor Troicki.