Alker matched his lowest 18-hole score on the Champions Tour by racking up eight birdies before finishing the round with an eagle on the par-5 18th in the inaugural Simmons Bank Championship on Friday in Little Rock, Arkansas.
The 53-year-old slipped past South Africa's Ernie Els for first place in the projected Charles Schwab Cup standings.
"You want to try to go low out here, just keep pedal to the metal and just try to shoot the best score," Alker said. "You look at the leaderboard and you saw 7s and 8s and thought just try to keep going."
The top 36 players in the standings after Sunday's final round at Pleasant Valley Country Club will advance to next month's season-ending Charles Schwab Cup Championship in Phoenix.
Fuji's Vijay Singh climbed from 34th to 15th in the projected standings after shooting a 64 to close the first round alone in second place, two shots behind Alker.
Denmark's Thomas Bjorn, South Africa's Retief Goosen and Jason Caron each carded a 65 to finish in a three-way tie for third at seven-under. All three are currently projected to finish in the top 36.
Richard Green, Cameron Percy and Steve Allan headed the nine Australians in the field, tied for 16th place, all three with plenty to play for in the remaining two rounds.Â
Green remains projected to be No.4 amid his great season while Percy is currently projected to be No.39 and Allan No.38.
Rod Pampling shot 70 and is projected to be No.34, with Stuart Appleby (70, projected No.33) and Mark Hensby (70, projected No.28) alongside.
Greg Chalmers (73, projected No.29) and Michael Wright (73, projected No.54) followed, ahead of David Bransdon (74, projected No.36).
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