TAIPEI, October 4, 2014 (AFP) - Lewton fired three straight birdies from the fifth hole onwards, before dropping a shot to reach the turn in 34.
He added one more birdie and one bogey on his way home for a three-day total of 212 at the Taiwan Golf and Country Club's Tamsui course.
"I got off to a really good start. The three consecutive birdies from the fifth hole kind of got my round going.
"I think I've learnt to play the golf course a little bit after missing the cuts in the last two years ... It has taken me a few rounds to get used to it," said Lewton.
In a day many players struggled to sscore under par, Filipino veteran Antonio Lascuna moved up with a second straight 69 to tie for second place on 213 alongside overnight leader Adilson Da Silva of Brazil.
Tour rookie Cameron Smith of Australia and compatriot Unho Park were one shot back in fourth place after both shooting 70s.
Spain's Javi Colomo carded a 69 to shared sixth place with Thai veteran Thaworn Wiratchant and India's Rahil Gangjee for a three-day total of 215.
Leading scores after round three (par 72):
212 - Steve Lewton (ENG) 70-72-70
213 - Antonio Lascuna (PHI) 75-69-69, Adilson Da Silva (BRA) 75-66-72
214 - Unho Park (AUS) 72-72-70, Cameron Smith (AUS) 72-72-70
215 - Javi Colomo(ESP) 72-74-69, Thaworn Wiratchant (THA) 72-73-70, Rahil Gangjee (IND) 74-71-70
216 - Lu Wen-teh (TWN) 74-72-70, Sam Cyr (USA) 71-74-71