Juan Martin del Potro won his fourth successive title on Sunday with a 6-3 6-3 defeat of Viktor Troicki in the final of the Legg Mason Classic.

The second-seeded Argentinian ran his winning streak to 19 matches, adding to a growing resume which includes titles in Stuttgart, Kitzbuhel and Los Angeles.

The highlight of Del Potro's breakthrough run occurred last weekend in Los Angeles when he defeated ninth-ranked American Andy Roddick in the championship match.

His latest win was a rather easy one as he needed just over 90 minutes to dismiss Troicki. He closed things out with his fifth ace of the match.

Serbian Troicki was playing in his first ATP final. Included in his run was a quarter-final upset of Roddick, who was the defending champion.