(CNN) -- Gregory Bourdy, Liang Wen-Chong, Charl Schwartzel and Robert-Jan Derksen share a slender one-stroke lead at the midway point of the Hong Kong Open.
Frenchman Bourdy, the 2008 Estoril Open de Portugal winner, dropped his third shot of the day at the last to let slip a potential outright lead and was forced to settle for a three-under-par second round 67.
Derksen (68) had led on 11-under but finished with back-to-back bogeys, while China's Liang boosted his slender hopes of winning the Asian Tour Order of Merit with a bogey-free five-under-par 65.
South Africa's Schwartzel (66) joined the trio on nine-under overall.
Singapore Open runner-up Liang also currently occupies the 60th and final qualifying spot for the season-ending Dubai World Championship, while Bourdy and Derksen must finish at least second in Hong Kong to stand a chance of heading to the Middle East for the lucrative showpiece.
"It was a good day. I was consistent but made a double bogey on the eighth and bogey on the 18th which was a shame with three putts," Bourdy told reporters.
"But my game was good and I am confident for the weekend. There are plenty of positives to take into the last two rounds and if I keep playing like this I will be OK on Sunday."
Thailand's Chinnarat Phadungsil carded a second consecutive four-under-par 66 to join South Africa's Rory Sabbatini (67) on eight-under, with U.S. PGA winner YE Yang (67), defending champion Lin Wen-Tang and David Dixon (both 69) in a group a further shot off the pace.
Rory McIlroy edged ahead in the battle for overall European supremacy after a two-under-par 68 pushed the 20-year-old to six-under overall alongside Singapore Open champion Ian Poulter, who shot a bogey-free 66, and two clear of Race to Dubai leader Lee Westwood.
First-round leader Udorn Duangdecha tumbled down the leaderboard as the Thai followed his storming 62 with a four-over-par 74.