Argentinian teenager Juan Martin del Potro claimed a third consecutive title with a 6-1 7-6 (6/2) victory over world number nine Andy Roddick at the Countrywide Classic in Los Angeles.

World number 24 Del Potro had never won an ATP singles title until last month in Stuttgart, but followed that triumph with another the following weekend in Kitzbuhel.

The third seed made a storming start to number three, breaking Roddick in the opening game of a 34-minute first set.

Roddick, who had not previously been broken in the tournament, was more competitive in the second set but had no answer in the tie-break as Del Potro won the final five points to claim the title.