By Steve Keating
NEW YORK, Aug 29 (Reuters) - Top seeds Serena Williams and Novak Djokovic were forced to take a backseat to America's latest tennis sweetheart on Thursday, as 15-year-old Catherine Bellis hogged the Flushing Meadows limelight once again.
However, Bellis, who shot from obscurity to fame with a shock first round win over Australian Open finalist Dominika Cibulkova, could not deliver the fairytale American tennis fans had hoped for, falling 6-3 0-6 6-2 to Kazakhstan's Zarina Diyas.
While former U.S. Open champion Andy Murray played in front of thousands of empty seats on the Arthur Ashe Stadium court, hundreds lined up at the entrances to a jam-packed Court 17, trying to catch a glimpse of "CiCi" - the teenager's nickname.
With hoards more gathered around giant screens outside the main stadiums, groans of disappointment could be heard across the sprawling U.S. National Tennis Center as the crowd watched the match slowly slip away.
"I think what surprised me is that I could really, like, stay with these pros," Bellis told reporters.
"I think today if I had played a little bit better, it would have been a different result. But, I mean, just that I can play with them is really good."
It was not all bad news for the home fans as five-time U.S. Open champion Serena Williams sailed through brisk winds to land comfortably in the third round of the year's final grand slam.
Gusty breezes led Williams to misfire for three double faults in her first service game before the two-time defending champion found her bearings to swat aside fellow American Vania King 6-1 6-0 in 56 minutes.
"It's so hard to play in the wind," said the world number one, seeking her 18th career grand slam singles crown. "I'm very happy to get through a solid match with the conditions today."
Wimbledon champion Djokovic followed Williams onto the Arthur Ashe Stadium court and was equally efficient, gliding past French veteran Paul-Henri Mathieu 6-1 6-3 6-0.
Djokovic echoed Williams' sentiments after advancing.
"It was very windy but I was able to adjust. I used my serve efficiently, getting them in," said the Serb, who pounded in 75 percent of his first serves, including 13 aces, without a double fault.
Most of the other leading seeds remained on course for an expected journey into the second week of the tournament.
Eighth seed Murray, who overcame cramping in his first-round victory, roared past unseeded German Matthias Bachinger in three sets to reach the third round.
Murray, the 2012 U.S. champion and 2013 Wimbledon winner, looked fresh and strong in cool, breezy conditions as he rolled to a 6-3 6-3 6-4 victory.
Canada's hopes of first grand slam winner also stayed alive as men's fifth seed Milos Raonic blasted his way into the third round with a 7-6 (4) 5-7 6-4 7-6 (3) win over Peter Gojowczyk while women's seventh seed Eugenie Bouchard, trying to reach a fourth consecutive grand slam semi-final, scored a 6-2 6-7 (4) 6-4 decision over Romania's Sorana Cirstea.
Ninth seed Jo-Wilfried Tsonga of France cruised by Aleksandr Nedovyesov of Kazakhstan 6-3 6-4 6-4 and big-serving American John Isner, the 13th seed, beat German Jan-Lennard Struff in straight sets.
Tenth seed Kei Nishikori of Japan had a shorter trip through to the third round as he advanced after Spain's Pablo Andujar retired while trailing 6-4 6-1.
Philipp Kohlschreiber, the 22nd seed, had an even quicker time booking a place in the third round as France's Michael Llodra retired after dropping the first set 6-2, due to an ailing elbow.
Hard-hitting American Sam Querrey limited his time spent on court against a healthy Guillermo Garcia-Lopez with his racket, beating the 28th-seeded Spaniard 6-3 6-4 6-4.
Querrey's win earned him the dubious honour of advancing to face Djokovic in the next round.
"Sam is one of the top Americans," noted Djokovic. "He has a big serve on any surface. If he serves well, he is dangerous."
A former world number one failed to survive the second round, however, as error-prone eighth seed Ana Ivanovic of Serbia was ousted by 42nd-ranked Karolina Pliskova of the Czech Republic 7-5 6-4.
Also shown the door was Australia's 2011 U.S. Open champion Sam Stosur, who lost a third-set tiebreaker 10-8 to Kaia Kanepi of Estonia.
Third seeded Wimbledon champion Petra Kvitova booked her expected place in the third round, however, with a 6-4 6-2 victory over fellow Czech Petra Cetkovska. (Editing by John O'Brien)