Beijing - US Open Champions Serena Williams and Marin Cilic have powered through their openers at the $5.4 million China Open Monday, with the women's number one crushing her opponent after being 5-0 down.
Spaniard Silvia Soler-Espinosa looked to be cruising to a memorable victory against the power-hitting American in Beijing as she raced to a five-game advantage within twenty minutes.
But Williams' response was ruthless, taking seven consecutive games to clinch the set with an incredible show of force.
A startled Soler-Espinosa took two games in the following set, but the number one seed in Beijing closed in on victory in 73 minutes with a 7-5, 6-2 scoreline.
It was a devastating comeback and a clear statement of intent from Williams, who fell at the first hurdle at the Wuhan Open last week after retiring from her game with a viral illness.
Williams revealed after her match in Beijing that she had undergone doubts about competing in the China Open, following her illness in Wuhan.
"I wasn't sure if I was going to play or not," the 33-year-old said.
"You know, I just started hitting a couple days ago, taking it day by day. Finally I decided I'm here, I may as well see what happens. Here I am."
The reigning champion in Beijing won her sixth US Open earlier this month, the 18th Grand Slam title of her career.
The queen of women's tennis said she fought hard in her opening match in Beijing to avoid a "bagel" -- a 6-0 set.
"I just didn't want to lose - I didn't want to lose six love," she said.
"I just started fighting. I was like - 'Just let me at least try to break here'."
Elsewhere in Beijing, 14-times Grand Slam winner Rafael Nadal returned to action after a three-month injury layoff, playing alongside Pablo Andujar in the doubles. However, the Spaniards were beaten by Tomas Berdych and John Isner 7-5, 4-6, 10-4.
Nadal is the second seed in the men's singles and will play Richard Gasquet of France Tuesday.
The biggest surprise of the day was in the women's singles where tenth seed Serb Jelena Jankovic was dumped out by Alize Cornet of France 7-5, 3-6, 6-4.
Home-crowd favourite Peng Shuai, who reached the US Open semi-finals earlier this month, beat compatriot Zhang Kailin 6-4, 6-1 to book her place in the next round.
Seeds Lucie Safarova and Ana Ivanovic also made it through their first-round matches.
Serb Ivanovic, a former world number one, defeated Switzerland's Belinda Bencic 6-2, 6-1.
The ninth seed in Beijing will play another Swiss player, Romina Oprandi, in the second round.
Thirteenth seed Czech player Safarova beat Italian Camila Giorgi 7-6 (7/3) 6-4 in her opening match.
In the men's singles competition fourth seed Cilic did not drop a serve in his defeat of Chinese wildcard Yan Bai -- but was brought to break point on his first two service games.
The Croatian, playing his first game since his convincing 6-3, 6-3, 6-3, victory over Japan's Kei Nishikori in New York, took 81 minutes to dispose of his opponent 6-3, 6-4.
Afterwards, he said he was still adjusting to playing competitively since his maiden Grand Slam victory.
"I felt that I was playing little bit better and better after the beginning," Cilic said.
"(I) was still a little bit rusty after a few weeks. Just to start the match, it was a bit different, different conditions."
The 26-year-old, who was a runner-up in Beijing in 2009 and 2011, is chasing points as he pushes to qualify for the ATP World Tour Finals in November.
The current world number nine is in fifth position in the race for the London tournament and must remain in the top eight if he is to make the season finale for the first time.
Elsewhere in the men's competition, fifth seed Grigor Dimitrov of Bulgaria won his match against Fernando Verdasco of Spain 6-1, 3-6, 6-3.
The China Open is being held at the Olympic Park in the Chinese capital and will reach its climax on October 5.