BANGKOK, Oct 11 (Reuters) Top seed Jelena Jankovic retired from the Bangkok Open after suffering from heat illness in her first round match with China's Zi Yan.
On a humid evening in the Thai capital, Jankovic let slip a one set lead to the gutsy Chinese and called it a day after a medical timeout, having lost the second set tiebreak.
The world number three had looked in good form during the first set, racing through her service games and unloading a torrent of topspin-loaded drives from her forehand and backhand to win 6-4 yesterday.
Jankovic was dictating the match from the baseline, forcing frequent errors from Zi, whom she had darting across the court for most of the first set.
But the determined Chinese battled back in the second, breaking Jankovic after four games as the heat and a series of marathon rallies took their toll on the Serb, who told medical staff she was experiencing breathing difficulties.
''The doctor asked me to stop the match. If I'd have continued I probably would have fainted and ended up in hospital,'' Jankovic said.
''I had bad luck, my body was tired and with the heat illness I couldn't continue in this way.'' Her retirement was the latest setback for Thai tennis following high-profile withdrawals of Rafael Nadal, Andy Roddick and Novak Djokovic at the ATP Thailand Open two weeks ago.
Rain caused the suspension of the match between American Venus Williams and Denmark's Caroline Wozniacki. Wimbledon champion Williams was close to victory with a 6-2 4-1 lead.
Chasing one of the final four berths at the season-ending championships in Madrid, Williams was in no mood to hang around, racking up the points with a series of ferocious serves and potent backcourt returns.
The match was due to resume on Thursday.
In earlier matches, defending champion Vania King beat fellow American Jill Craybas 6-1 3-6 6-2 to progress to the second round.
Frenchwoman Camille Pin, Italian Flavia Pennetta and Taiwan's Chan Yung-jan were other first round winners on Wednesday.
REUTERS BJR KP1004