Fred Couples recovered from an opening bogey on Friday to shoot a one-under 70, which helped him maintain a share of the lead after two rounds of the Charles Schwab Cup Championship.

Couples finished 36 holes at four-under-par 138. He was joined there by David Frost and Michael Allen, who both shot two-under 69s in round two.

Mark Calcavecchia, Bernhard Langer and Jay Don Blake all posted three-under 68s in the second round. They were matched in fourth place at minus-three by Kenny Perry, who shot 69 on Friday at TPC Harding Park.

Jay Haas played alongside Couples in round two and struggled with a bad back en route to a one-over 72. Haas is alone in eighth at minus-two.

The other battle this week is for the season-long Charles Schwab Cup. Tom Lehman tops the list and is one of five players who can win the $1 million annuity.

Lehman shot 73 to slide into a share off 11th at even-par 142.

There are four other players who can pass Lehman -- Calcavecchia, Peter Senior, John Cook and Russ Cochran.

Senior stumbled to a five-over 76 to fall into a tie for 24th. Two-time defending champion Cook shot 73 for the second straight day and shares 21st, while Cochran carded a two-under 69 to climb into a tie for 14th at plus-one.