Frenchman Richard Gasquet became the first high-profile casualty at the Shanghai Masters on Tuesday, swiftly followed out of the exit door by compatriot Gilles Simon as organisers scrambled to keep the storm-hit event on track.
Drenching rains, which flooded streets near the venue -- the lingering effects of Typhoon Fitow -- forced a switch to indoor courts at the Qizhong Tennis Center, with tournament chiefs attempting to make up for lost match time the previous day.
Ninth-seed Gasquet's tame 6-3, 6-4 defeat to Vasek Pospisil deals a heavy blow to his hopes of reaching next month's World Tour Finals in London, which feature the season's top eight players. Gasquet is currently ninth in the Race to London.
Canada's Pospisil, ranked 43rd in the world, broke in the fourth game of the first set and again at the start of the second in a match lasting 69 minutes, with the Frenchman unable to muster a single break point.
Simon, the 13th seed, was also a first-round loser, slipping to a 6-4, 6-3 defeat to countryman Benoit Paire. But Japan's Kei Nishikori reversed the slide for the seeds, comfortably seeing off the challenge of Bulgarian Grigor Dimitrov 6-3, 6-4.
Canadian 10th seed Milos Raonic won his late evening match against Michal Przysiezny 6-4, 6-4.
Shanghai on Tuesday saw its greatest daily average rainfall since 1961, web portal East Day reported, citing municipal weather authorities. From 8:00 pm on Monday until noon on Tuesday, the city received 15.3 centimetres (6.02 inches) of rain.
The wet weather meant a number of changes to the schedule throughout the day, with doubles matches postponed in an effort to complete all the first round matches before the likes of Novak Djokovic and Rafael Nadal make their entrance.
Veteran Lleyton Hewitt earlier lost 6-4, 6-2 to Andreas Seppi, missing out on the chance of a second round match-up against old rival and fifth seed Roger Federer.
Hewitt, 32, who has slipped out of the world's top 50, started strongly, breaking at the first opportunity and taking a 3-0 lead. But Seppi withstood the charge, winning five games in a row to seize the initiative.
The Australian wildcard showed only occasional glimpses of his fighting ability as world number 22 Seppi cut down on his error count and broke Hewitt twice at the start of the second set.
"He played a lot better," said Hewitt. "He hardly missed a ball after the first three games. I had chances to go up four-love. From then on, he played really well. He served better than I've seen him serve before."
"I served in patches. Probably when I was down breakpoints and stuff, I didn't get enough first serves in," added Hewitt. "He's such a tough player to play when the ball is on his terms."
Among the other winners on Tuesday were Spanish seeds Tommy Robredo and Nicolas Almagro.
The top eight seeds all have a bye into the second round.