Louis Oosthuizen accelerated his remarkable comeback from US Masters heartbreak as he seized control of the rain-interrupted Maybank Malaysian Open on Saturday.
The world number 19, completing his second round after a heavy storm on Friday, fired two birdies on his last six holes for four-under-par 68 and a one-shot lead over a field containing four other major-winners.
Oosthuizen lost out to Bubba Watson in a Masters play-off less than a week ago, and he has contended with a 30-hour journey across 12 time zones, plus extreme heat, a tropical storm and travelling with his two young children.
But the unflappable South African has oozed class at the par-72 Kuala Lumpur Golf and Country Club and he followed up his first-day 66 for an aggregate score of 10-under 134 in the $2.5 million European and Asian Tour event.
Fellow South Africans Jbe Kruger and Hennie Otto, and Scotland's Stephen Gallacher, are a stroke back in joint second, while 2010 PGA Championship winner Martin Kaymer, a former world number one, is three off the pace.
"It's nice playing in the mornings here -- you feel loose because it's so hot," Oosthuizen said.
"I felt comfortable this morning, I had a good night's rest, felt comfortable on the range and started off with hitting a few good shots."
The 29-year-old now has a few hours' wait before starting his third round in the steamy Malaysian capital, where further storms are forecast on Saturday following Friday's deluge.
"I'm probably going to just hang out here. I brought the laptop with me so I'm probably just going to surf the Internet and just sit and wait," he said.
Oosthuizen's close friend Charl Schwartzel, the 2011 Masters champion and the first-round leader, gave up three shots in his second round to drop to five strokes back in a share of 13th.
Six-time European Tour winner Alvaro Quiros shot 68 to lie six off the lead and the defending champion, 18-year-old Italian Matteo Manassero, was eight shots adrift.
New Zealand's Michael Campbell, the 2005 US Open winner, survived the level-par cut at one-under but Todd Hamilton, whose sole major was in 2004, was eliminated after finishing four over through 36 holes.