 He carded a one-under 69 in the final round to finish with a total of 275 (-5) and win the tournament by one stroke over Dustin Johnson and Louis Oosthuizen.Spieth had begun the day in a four-way tie for the lead and played in the penultimate group alongside Branden Grace.He opened his final round with a bogey to fall behind, but then a run 12 pars and two birdies in his next 14 holes moved him into a tie for the lead with Grace at five under par.