BETHESDA - Bill Haas fired a five-under par 66 on Sunday to win the $6.5 million US PGA National, capturing his fifth career title and leaping into the top 10 on the tour’s season money list.The 31-year-old American took the top prize of $1.1 million at Congressional Country Club by finishing 72 holes on 12-under par 272, beating countryman Roberto Castro by three strokes. South Korean rookie Lee Dong-Hwan made nine birdies in a sizzling round of 64 for his best finish in 18 US PGA starts, a share of third with American Jason Kokrak on 276, one shot ahead of 2009 British Open winner Stewart Cink.US prodigy Jordan Spieth, trying at 19 to become the youngest US PGA Tour winner since 1931, fired a 69 to finish sixth on 278. –AFPHaas, who has $2.76 million this year with seven top-10 finishes, also won the 2010 Bob Hope Classic and Viking Classic, the 2011 Tour Championship and playoff title and last year’s Northern Trust Open at Riviera.At one point there were five players level for the lead at seven-under — including Haas, Castro, US teen star Jordan Spieth, American Jason Kokrak and Argentina’s Andres Romero — with three others only one stroke adrift. Haas broke open the tight battle with three birdies in a row, starting with a 10-foot birdie putt at the par-4 eighth, following with a 12-foot birdie at the par-5 ninth and ending on a 10-footer at the par-3 10th to reach 10-under.Castro, who led or shared the lead after each of the first three rounds, made an eight-foot birdie putt at the ninth to stay two back, squandering a chance to move closer with a seven-foot birdie miss at the 11th. Haas avoided stumbles by making tense six-foot par putts at the 13th and 15th, although Castro stayed two back by following a 10-foot Haas birdie putt at the par-4 14th with an eight-foot birdie putt of his own. At the par-5 16th, Haas dropped his third shot inches from the cup for a tap-in birdie to reach 12-under, stretching his margin over Castro to three shots, and then parred the last two holes to secure the triumph. Lee’s superb effort came a day after firing a 75 and making an obscene gesture at the 12th hole that was caught by television cameras.“It was just out of frustration,” Lee said. “I aimed (the gesture) at the ball, not anyone in the crowd. “I regret what I did regardless of the reason. It’s something I shouldn’t have done. Everybody makes mistakes. I made this mistake and I’m just going to learn from this.” Lee, a two-time Japan Tour winner who captured last year’s PGA Qualifying Tournament, birdied the par-3 second then ran off five birdies in a row starting at the par-4 fourth.“The key was being able to make those consecutive birdies,” Lee said. “I knew I was far back from the leader so I just kept in my mind and played hole by hole. I just tried to empty my mind and just play my game.” After stumbling with bogeys at the 10th and par-4 11th, Lee sank a 38-foot birdie putt at the 12th, an 18-foot birdie putt at the 15th and after scrambling for two par saves closed with a 24-foot birdie putt at the 18th.“The two par saves I had on 16 and 17 were the two most important putts I made,” Lee said. “Because I was able to save par, that set up the environment, the atmosphere for me to birdie the last hole.” Lee, trying to win enough money to keep his card for 2014, took home $377,000, which was $12,170 more than what he had previously won this season.