Having fallen early last week in Shenzhen, Hsieh's Australian Open preparations were dealt a further blow when she lost a two and a half hour thriller with Peng, 62 67(4) 76(4).
The last time the two met, Peng prevailed over three memorable sets at the Olympics last summer. However, for the first hour on court in Hobart, the match was anything but memorable for No.1 seed Hsieh, Peng racing through the first set before opening up a seemingly insurmountable 5-2 lead in the second.
Yet, at 5-2 down, Hsieh somehow roused herself to win the next three games and force a tie-break, which she won to improbably level the match at one set apiece.
The deciding set followed a similar pattern, with Peng opening up a 4-1 and then 5-3 lead, only to see Hsieh peg her back. This time, though, Peng was not to be denied, finally ending the World No.26's resistance on her fifth match point.
"It was so tiring out there!" Peng said. "We are good friends and often practice together so I think we both know each other's game so well and it means we have very long rallies.
"The match was really similar to the one at the Olympics: I won the first set, then she came back and in the third set it was again a really tight match.
"She has good hands, with the drop shot and the angles, and I was running from side to side. I was just trying to fight out there and I'm really happy this was enough to win and get in the second round."
Bratchikova made most of the early running, reeling off four games in a row on her way to the first set. The second was far tighter, but with the winning line in sight, Bratchikova faltered, dropping serve at 5-5 to hand the set and the initiative to Cirstea.
After leveling the match, the Romanian steamrollered through the decider, a 36 75 62 win setting up a second round meeting with qualifier Lauren Davis.
"I started out a bit shaky and it took me a while to get used to the conditions," Cirstea said. "But I'm really happy with this win and how I fought my way back into the second set.
"I was playing well in the third set and hopefully I can play even better in the second round."
There were mixed fortunes for the other three seeds in first round action, with wins for Yaroslava Shvedova and defending champion Mona Barthel, who saw off Lourdes Domínguez Lino and Ashleigh Barty, respectively, while Francesca Schiavone was edged out by Kirsten Flipkens, 26 63 76(3).