KIAWAH ISLAND, S.C. (AP) — Phil Mickelson had a clear picture that he could win a major championship at age 50. And that’s what he did at the PGA Championship at Kiawah Island. He’s now the oldest major champion in history. But for all his skill and imagination, this one required more concentration. Mickelson has spoken of mental lapses in the past month. He says he played more golf to gain mental stamina. And, for the most part, he didn’t hit a shot until he could see a picture of what he was trying to do. Mickelson still feels great physically. What’s more, he hasn’t ruled out winning more majors.