(CNN) -- In-form Gonzalo Fernandez-Castano and Mark Brown shared the lead after the first round of the Ballantine's Championship at the Pinx Golf Club on Jeju Island.
New Zealander Brown lines up a putt during his opening round of 65 in South Korea.
Spaniard Fernandez-Castano and New Zealander Brown finished second and third at last week's Volvo China Open and the pair opened up in South Korea with seven-under-par 65s.
A three-strong group are one shot back with Thailand's Thongchai Jadee shooting four straight birdies on his way to a 66.
He also eagled the 10th to join Korea's Kang Kyung-Nam and Dutchman Robert-Jan Derksen on that mark.
Meanwhile, Robert Dinwiddie, Alessandro Tadini and Jason Knutzen are all on five-under-par.
Three-time major champion Ernie Els took advantage of an eagle at the 10th to be in contention on four-under, the same mark as world number nine Henrik Stenson of Sweden.
But defending champion Graeme McDowell of Northern Ireland was left shaking his head after a sorry four-over-par 76. It leaves him 11 shots behind the leading pair, who are full of confidence.
Brown, who has forged his reputation on the Asian Tour which is co-sanctioning the event, is setting his sights high. "I'm aiming to peak for a major in July back in Europe, it's a step in the right direction," he told the official Tour Web site www.europeantour.com.
Fernando-Castano had six birdies and an eagle on the accommodating 10th as an afternoon starter. "It's all good to start. It's always important to start with a good round," he said. "But still, it's 54 holes to go, so it's still a long way."