Left-hander Richard Green celebrated Australia Day by joining South African Retief Goosen in a share of the lead after the second round of the Qatar Masters on Friday.
Goosen, the overnight pacesetter, carded a four-under-par 68 to move to 11-under before Green joined him on top of the leaderboard with a seven-under 65.
Australian left-hander Nick O'Hern (69) is third on nine-under after letting slip a share of the lead with two late bogeys.
Holder Henrik Stenson (68) of Sweden, Briton Paul Lawrie (67), Spain's Miguel Angel Jimenez (70) and China's Liang Wen-Chong (67) are next best on eight-under.
World number eight Goosen is looking to improve his ranking by claiming his first European Tour victory since the South African Open in December 2005.
Helping the twice former U.S. Open champion to attain his goal is Florida-based coach Gregor Jamieson.
"My driving was much better today," Goosen told reporters. "I hit 11 fairways which was not bad.
"I am pleased with my decision to begin working with Gregor. I felt I needed something different as I was struggling so much."
Green is trying to end a long European Tour victory drought.
His last win came when he defeated countryman Greg Norman and Briton Ian Woosnam in a playoff at the 1997 Dubai Desert Classic.
"I have had a hatful of second places and strong results since winning in Dubai and it would be nice to have another victory," said Green. "It would be fantastic as I seem to play well in this part of the world."
Stenson is attempting to become the first player to win the title twice in the 10-year history of the event.
"I feel as though I have done a pretty good job as defending champion so far," said the Swede.
World number five Ernie Els, the 2005 champion, carded a 71 for a four-under total of 140 in his first strokeplay event of the year.
Britain's Darren Clarke, also competing in his opening strokeplay tournament of 2007, missed the cut with rounds of 75 and 76.