By Marcus ChhanFollow @@MarcusChhan
The US$1.4 million tournament teed-off at Sentosa's Serapong Course on Thursday with Spaniard Azahara Munoz firing a blistering seven-under to take the lead.
Tseng is three shots back at four-under but it would have been even more had it not been for the Taiwanese star's brilliant close at the 18th hole.
The 24-year-old hit a spectacular shot off her 3-wood to reach the par-five in two and then thrilled the crowd by draining a long putt for eagle to move up the leader-board into a four-way tie for seventh.
"After the last putt dropped in? Yes, i am pretty happy [with my putting]," Tseng told FOX Sports.
"I was thinking I should go practice [after my round] but now maybe I don't have to!"
"It is always good to finish strong and on the last hole make birdie or eagle. I still need to work on my putting. Today [Thursday] I was struggling a little on the back-nine.
Tseng is a hugely popular figure in Taiwan and it was not surprising to see a significant number of her compatriots warmly applauding her as she stepped onto the first tee at 10.04 am Thursday morning.
In her group was also defending champion and five-time LPGA Tour winner Angela Stanford as well as Spain's Beatriz Recari.
And it only took Tseng until the second hole to register her first birdie of the tournament. As Tseng struck her tee shot at the 156 yard par-three second, a woman screamed "in the hole" and she wasn't far wrong as the ball landed close to the pin.
Tseng would then move to two-under after four with some aggressive play on the par-five which led to an easy birdie chance from within five feet.
She would bogey the next hole after a poor third shot saw her needing to make a putt from the edge of the green for par which she missed.
But, then she went back to two-under with a birdie on the seventh hole - another par-five at 493 yards long.
However, missed birdie putts on eight, nine and 10 would signal the start of a dip in Tseng's game in the opening round of this invitation-only tournament.
And she did well to save par on the 481 yard par-five 12th after seeing her second shot miss the green and land in the rough and under a tree. Standing in between her and the hole was a footpath, a bunker and a greenside slope with the flag close to the top of the mound which did not leave her much room to get close to the pin. But she managed to get the shot up and down quite nicely and saved par with a two-putt.
On the par-four 16th she did well to save par once again. Off the tee she found the left fairway bunker which forced her to leave her second shot short of the green. From there she hit an accurate pitch shot to within a few inches of the hole to tap-in for par.
Another par followed at the par-three 17th.
"Par is your best fiend," she said.
Tseng added: "It's a tough golf course and you just need to be patient".
This set her up for the thrilling finale on the 18th at Serapong. Unbeknownst to the crowd, Tseng had made a bet with her manager that if she shot a 68 in the first round she would have to go skydiving with Tseng in Hawaii. If she shot 69, the bet would be called a draw while anything higher and the world's top golfer would have to foot the bill for a Louis Vuitton bag for her manager.
And as the ball trickled into the cup from a long way out to seal an eagle and a score of 68, Tseng's manager's worst skydiving fears were realised.
"I was looking at her and I saw her face. I think she wants to cry," she said.
The HSBC Women's Champions event in Singapore is a 72 hole individual stroke play competition over four days with no cut.
It is widely considered amonst the players as 'Asia's Major'.