Martin Kaymer scores second 65 in two days at U.S. Open . ( CNN ) -- Martin Kaymer stretched his lead at the top of the U.S. Open leaderboard with a second successive round of 65 at Pinehurst No . 2 Friday . German makes lowest 36-hole total in tournament 's history . Former world No. 1
Martin Kaymer scores second 65 in two days at U.S. Open . German makes lowest 36-hole total in tournament 's history . Former world No. 1