ST. LOUIS (Reuters) – Brooks Koepka was clinging to a two shot lead at the PGA Championship on Sunday but back-to-back bogeys opened the door for a back nine shootout with Tiger Woods and defending champion Justin Thomas among those taking aim at the title. Koepka, the twice defending U.S. Open champion, started the day two shots clear of the field and had been grimly hanging onto top spot until rolling in birdies at seven, eight and nine to undo much of the earlier damage and provide a small bit of relief. But the big-hitting American’s wobble had given a tightly packed field hope. Thomas was quick to jump mixing five birdies against a single bogey to get to four-under with six to play and move into a share of second alongside Belgian Thomas Pieters. Lurking just three back are Woods and Australian Adam Scott, who was playing in the final pair with Koepka. With Woods in the running to win his first major in a decade, Tiger-mania was at a fever pitch at a steamy Bellerive Country Club. The 42-year-old American whipped the massive gallery trailing him into a frothing frenzy with birdies at the second and third holes. But after his only bogey on the outward nine at the sixth, Woods, wearing his traditional final round red shirt and black slacks, sent the crowd into absolute hysteria with back-to-back birdies at eight and nine to vault into a tie for second. Koepka, hearing the thundering roars as they washed over the parkland layout, corrected a mid-round wobble with three straight birdies to regain control of the leaderboard.