Chang given tough lesson by Caroline Wozniacki
Top seed Caroline Wozniacki wasted no time in reaching the last 32, hammering Kai-Chen Chang
Wozniacki, who lost to Kim Clijsters in last year's final, has dropped just two games in her first two matches at Flushing Meadows.
"I've been playing really great tennis, I'm feeling good so no worries," Wozniacki said.
"It's just about winning and getting through to the next rounds.
"As long as I win it doesn't really matter what the match looks like."
Fourth seed Jelena Jankovic made nearly 60 unforced errors but came through her clash with Mirjana Lucic 6-4, 3-6, 6-2.
Vera Zvonareva cruised through the opening set against Sabine Lisicki but had to come back from a break down in the second to secure a 6-1, 7-6 victory.
Former champion Svetlana Kuznetsova had no trouble in beating Latvia's Anastasija Sevastova 6-2, 6-3 but 22nd seed Maria Jose Martinez Sanchez lost in straight sets to Switzerland's Patty Schnyder.
