(Reuters) - Battle-scarred Argentine Juan Martin del Potro clinched his 21st career title with a 6-4 6-4 win over Kevin Anderson in the Mexican Open final in Acapulco on Sunday.

The week after losing to Frances Tiafoe in the second round at Delray Beach Open in Florida, the former U.S. Open champion dropped only one set in four matches on the Acapulco outdoor hardcourt on his way to the title.

One break in each set was enough to give del Potro his first title of the year and the world number nine did not face a single break point as he improved his perfect career record against the big-serving South African to 7-0.

Anderson, ranked a spot above Del Potro in the world rankings coming into the tournament, was seeking his second consecutive title after winning the New York Open two weeks ago.

When Anderson gets it right with his booming serve he can be difficult to break down but 29-year-old Del Potro was able to feed on the South African’s weaker second serve to get the crucial breaks.