No let-down as Peng reaches US Open last 16
Peng Shuai of China celebrates after defeating Agnieszka Radwanska of Poland during the 2014 US Open women's singles match on August 27, 2014 in New York - by Kena Betancur
Peng, showing no sign of a let-down after her second-round upset of fourth-seeded Agnieszka Radwanska, dispatched 28th-seeded Italian Roberta Vinci 6-4, 6-3 in just an hour and a quarter on a sun-splashed Louis Armstrong Stadium.
"I was really nervous," Peng said, afraid that the adrenaline would have her belting her groundstrokes to the back fence.
She managed to keep the nerves in check to equal her best US Open showing -- a fourth-round appearance in 2011.
"I have a lot of motivation," said Peng, who knows she has the eyes of China on her with compatriot Li Na sidelined by injury. "I wanted to fight and I really enjoyed the play."
Ninth-seeded Jankovic was runner-up in 2008 -- her only appearance in a Grand Slam final to date and one she's keen to repeat, if not improve upon.
"I feel hungry, I want to do well again," said Jankovic, who called the bustling US Open her favorite tournament -- even if it means coping with brash fans who ask mid-match for a quick photo pose.
Such distractions didn't stop Jankovic from sweeping past Sweden's 96th-ranked Johanna Larsson 6-1, 6-0 in just under an hour.
"It was nice to get off the court quite fast," Jankovic said. "It was quite hot out there. I played a solid match. I was patient. I waited for my chance to execute, and that's what I did."
World number two Simona Halep, seeded second behind five-time champion Serena Williams, was also vying for a fourth-round berth Friday, along with fifth-seeded former champion Maria Sharapova and two-time winner Venus Williams.
Although Venus Williams won back-to-back titles in 2000 and 2001, she's enjoying her best campaign since a semi-final run in 2010 was followed by three-straight second-round exits.
The 19th-seeded American will tackle 13th-seeded Italian Sara Errani, while French Open champion Sharapova will face a tough test against big-hitting German Sabine Lisicki.
Roger Federer's quest for a sixth US Open title continues Friday night against the big-serving Australian Sam Groth.
The 104th-ranked Groth is averaging more than 16 aces per match this season, but in his first match against a top 10 player he'll be walking into the lion's den.
Federer boasts a 23-1 record in night matches on Arthur Ashe Stadium court.
In other men's second-round matches, fourth-seeded David Ferrer faces Australian wildcard Bernard Tomic.
The Spaniard, who fell to Federer in the final at Cincinnati this month, has won both prior encounters with Tomic.
Wimbledon semi-finalist Grigor Dimitrov, who was 0-3 at the US Open before this year, seeks a third-round berth against Israel's Dudi Sela and sixth-seeded Czech Tomas Berdych takes on Slovakian Martin Klizan.