The New Zealander shot a seven-under 64 in the second round of the Charles Schwab Cup Championship to take a one-shot edge over Irishman Padraig Harrington Friday in Phoenix.
Alker and Harrington entered the season finale Nos 1 and 2 in the Schwab Cup points race. Alker held a commanding 617Â 980-point lead, meaning Harrington needs not only to win but to receive some help in the form of Alker dropping down the leaderboard at Phoenix Country Club.
Alker made seven birdies on Friday to get to 13-under 129. He is the only player in the field who's bogey-free through 36 holes.
"I know what I've got to do, the numbers are all there," Alker said. "It's kind of black and white. I just try and put myself in position to win a golf tournament, that's big for me. Yeah, (Harrington) played well today, so I've got to keep hammering those birdies out."
Harrington also shot a 64 to reach 12 under, birdieing four of his first five holes and adding four birdies and a single bogey on the back nine.
They'll be in the final pairing together for Saturday's third round.
"Look, he's playing very well," Harrington said of his opponent. "I played with him every week in the playoffs at this stage and he's not backing down. ... You couldn't begrudge him where he is at the moment, you couldn't begrudge him winning this outright, but I'll try and do that the best I can."
Retief Goosen of South Africa (64 Friday) and Brian Gay (65) are tied for third three strokes back at 10 under. Miguel Angel Jimenez of Spain (66) and Stephen Ames of Canada (68) are tied for fifth at 9 under, while Scotland's Colin Montgomerie (66) is in seventh at 8 under.