Rio de Janeiro: China's Zheng Saisai stunned fourth seed Agnieszka Radwanska at the Olympics on Saturday, carving out a 6-4, 7-5 win as the Polish star paid a heavy price for a marathon 55-hour trip to reach Rio.
Zheng, the world number 63, made the most of a lacklustre performance from Radwanska who had to cross the Atlantic Ocean twice, racking up 14,000km and only arrving in Brazil on Wednesday night.
Radwanska had been playing at the Montreal WTA tournament last week but was stranded in the Canadian city when her connecting flight to Miami was cancelled due to a mechanical failure.
She flew to New York but was unable to make it to Florida due to adverse weather conditions, so jetted to Lisbon before flying to Rio.
"I spent three days in an airport so that was not the best preparation. I could have used more practice," said former Wimbledon runner-up Radwanska.
"I just didn't have enough time."
Zheng's win was the second top victory of the day for China after national number one Zhang Shuai saved three match points to beat Swiss 12th seed Timea Bacsinszky 6-7 (4/7), 6-4, 7-6 (9/7).
Zhang next faces either Germany's Laura Siegemund or Bulgaria's Tsvetana Pironkova, while compatriot Zheng takes on Russia's Darya Kasatkina.
Zheng, the world number 63, said she realised that Radwanska had been struggling.
"She didn't play her best tennis. I know she arrived late so I am really lucky," said Zheng who had her own dramas in Montreal.
She lost in the first round in Canada and accused the tournament of being "unprofessional" after a blunder with the stringing of her racquets.
"I was really relaxed today with the happiness of playing for my country," Zheng added.
For world number 51 Zhang, 2016 has proved to be an encouraging year on tour.
Her run to the Australian Open quarter-finals ended a depressing run of 14 first round exits at the Grand Slams, a record stretching back to the 2008 US Open.
"It was a tough match. She had three match points, it's a big win," said Zhang.
"Point by point is just 20 seconds so I didn't try to think too much but I just thought I don't want to go home so early. I like Rio, I want to stay here."
Veteran Peng Shuai was unable to make it three wins for China when she lost a 6-4, 6-7 (5/7), 6-3 to Britain's Heather Watson.
The British player tackles Ukrainian 15th seed Elina Svitolina for a place in the third round.
Ivanovic crashes out in windy Rio
Former world No. 1 Ana Ivanovic exited the Olympic Games in the first round on Saturday, though the Serb refused to blame the wind or soaring temperatures that some players said were making it tricky to play in Rio.
Ivanovic went one set up against world No. 12 Carla Suarez Navarro before losing the next two error-strewn sets to the Spaniard. Ivanovic lost 2-6 6-1 6-2.
"It was a tough draw for the first round," said Ivanovic, the former French Open winner currently ranked as world No. 26.
"I had a chance to come back in the third set but every time I came close to pegging her back, I missed the opportunity," she added.
Ivanovic's match, like all the others on center court, was played in a stadium that was more than half empty, something likely to disappoint organizers.
But the size of crowds didn't bother Japan's Kei Nishikori, who opened the men's singles tennis tournament on center court by knocking out Spain's Albert Ramos-Viñolas with ease, winning 6-2 6-4 in two sets.
Nishikori said he didn't care if stadium was full or empty as long he kept winning. "That’s the most important (thing)," he added.
Though one issue that impacted Nishikori's contest and most of the matches on a hot and humid day was wind, with breeze drifting across from the ocean making conditions tricky.
"Here it’s very difficult to play because it’s fairly open, there is constantly some kind of wind," said Croatia's Marin Cilic, who beat Bulgaria's Grigor Dimitrov 6-1 6-4.
One person who thrived in the Rio sun was Australia's John Millman, becoming the first Olympian ever to win a men's singles match without losing a game.
Millman's "double-bagel" 6-0, 6-0, victory against Lithuania's Ricardas Berankis came after several shoulder surgeries that threatened his career. The Australian also took part in the late-night opening ceremony, which many other Olympians competing early on Saturday skipped.
"I couldn't miss the (parade). That was a really stirring moment for me. It's hard to explain the emotions I got walking into that stadium, and obviously that carried over to today," said Millman, 27.
(With inputs from agencies)