She was in a similar position last week in Thailand but faltered and finished joint third. With the season barely three weeks old, it was an important lesson, said the 28-year-old, who is on 11-under 133 and holds a two stroke lead over six players tied on 135.
"Any time you come into the season, there's unknowns of how your game is going to come out and how you're going to play. It was the first time this year that I was under pressure with the lead and you just never know how your body is going to react even though you've been there before," said the winner of the 2012 Player of the Year award.
"Last week my putter just went sideways. I don't know what happened. But I feel a lot more comfortable with my putter this week. Last week I definitely was trying to force some putts and hit them too hard and through the breaks, so it's really important for me to just stay patient this week."
Besides victory at the US$1.4 million event at Sentosa Golf Club, the world No. 4 also has loftier dreams for herself - to supplant current world No. 1 Yani Tseng as the best female golfer on the planet.
"From the middle of last year that was one of my goals, to track down Yani. It still is," added Lewis whose best finish in three previous appearances in Singapore was tied-ninth in 2011. "I didn't play well last weekend but I still finished third and that helps me in that move to No. 1."
She is not the only golfer seeking to replace Tseng. South Korean and world No. 2 Na Yeon Choi could take over the top spot from the Taiwanese with a victory on Sunday on The Serapong course. Choi, who began her back nine with three straight birdies and matched Lewis' 66 on Friday, is among that group of six players within touching distance of the lead.
Said Choi, the reigning US Open champion who also birdied her opening and closing holes: "I had a great day today. I had a really good warm up this morning and I felt great. The three birdies in a row gave me good momentum and I finished strong on the 18th."
Also finishing strongly was Thai teenager Ariya Jutanugarn, 17, who nearly holed her approach on the par-five 18th for an eagle three. She eventually tapped in for a birdie and another 66 to sit joint-second alongside the likes of South Koreans Chella Choi (67) and Sun Young Yoo (68), American Paula Creamer (67) and overnight leader Azahara Munoz (70) of Spain.
Said Munoz: "It's a really hard course. I'm hitting really good shots but just not making as many putts as I did yesterday. I had a lot of downhillers today and I kept thinking that they were faster than they were and missing them short. But other than that I played really well and I'm really excited for the weekend."
So is Creamer, who despite a sore shoulder and whiplash after a car collision last week in Thailand, has performed brilliantly through the pain. She said, "Near the end of the round it gets a little sore. That's to be expected. I'm just glad to be out here and playing golf and I have no expectations whatsoever. It's funny how when you play a little bit better that happens."
Scotland's Catriona Matthew is six shots off the lead after carding a three-under 69 but England's Jodi Ewart Shadoff fell further off the pace with a 71.
"I didn't really do anything great all day," Lewis, who led after two rounds in Thailand last week but eventually finished tied for third, told her post-round press conference.
"I kind of just plodded my way around, made birdie on the first hole, made a good 25-footer, and that definitely got things started on the right foot.
"But I hit some bad shots, I hit some good shots, and just kind of made a few putts in between but I'm not going to complain about 66.
"If you try to go at a pin you probably shouldn't, you're going to pay for it, you really just have to play smart."
It was however, a day to forget for top ranked Tseng, who could only muster a disappointing 73 and is tied for 21st on 141. Host Singapore's sole representative Christabel Goh shot 78 and is last in the 61-woman field on 14-over 158.