Jason Day remains in a share of the lead after the second round of the US PGA Tour play-off event in Boston.

Day overcome strong afternoon winds to card a bogey-free 4-under-par 67 at the Boston TPC.

American Brandt Snedeker has joined Day at the top of the leaderboard after carding a seven-under 64.

Americans Matt Kuchar and Charley Hoffman are equal second on 11-under, while England's Luke Donald is next on the scoreboard at 10-under.

Last year's Deutsche Bank winner Steve Stricker and D.J. Trahan are equal sixth on nine-under.

Phil Mickelson fired a six-under 65 to move to eight-under overall.

Tiger Woods saved face after a poor opening round with a six-under 65 to keep him well clear of the cut.

The world No.1, who was blooding a new swing in Boston, said he felt motivated to improve on his one-over 72 on Friday.

Steve Elkington was the only Australian to miss the cut, which means he will not advance to next weeks US PGA Tour play-off event in Chicago.