BETHESDA, Md. —
Castro, part of a four-way tie for the lead at the start of the final round, made Haas work for it.
"He didn't make any mistakes, and the birdies on 9 and 10 were big," Castro said after his 69.
The other leaders fell away. Andres Romero had a double bogey on the fourth hole and shot 75. James Driscoll didn't make a birdie in his round of 74.
Jordan Spieth, the 19-year-old from Texas who needs a win to become a PGA Tour member and be eligible for the FedEx Cup playoffs, started his day by holing out from a fairway bunker for eagle and chipping in for birdie to tie for the lead. He dropped a shot at No. 11 — the hardest hole at Congressional — about the time Haas was on his critical run of birdies. Spieth had a 69 and finished sixth, pushing his earnings for the year over $1.1 million.
Castro bogeyed the opening hole, and that was his only mistake. He was one shot out of the lead at the turn, couldn't match birdies with Haas at the par-3 10th, and then stuck with him the rest of the day.
"It helped that Roberto played so well," Haas said.
Haas, who finished on 12-under 272, never allowed himself to think about winning, even after he seized control around the turn. Congressional wouldn't let him. Even though he made 15 birdies on the weekend, he remembered the triple bogey on the 11th hole Saturday that temporarily derailed him.
This time, he found the fairway, hit onto the green, took two putts for par and exhaled.
Haas saved par from a bunker on the par-3 13th with a 6-foot putt that swirled 360 degrees around the cup before falling, and then picked up an unlikely birdie on the 14th when his 9-iron was drifting toward a mound covered with shaggy rough to the right of the green. It hopped off the mound to about 10 feet, and he went from a possible bogey to a birdie when he made the putt.