Novak Djokovic made his victory on James Blake in Miami Masters

Runaway ATP leader Novak Djokovic polished his win-loss record this season to 20-0 as he crushed American James Blake 6-2, 6-0 to advance to the fourth round of the Miami Masters.

The second-seeded Serb barely needed an hour on Sunday to mow down Blake, a fading force at age 31 who was once a top-five player.

Djokovic has not lost a match since November and has won his past 21 on the trot dating to the Davis Cup final in December.

Del Potro downs Soderling

The comeback of the unseeded Argentine Juan Del Potro gained pace with the former U.S. Open champion upsetting fourth seed Robin Soderling 6-3, 6-2.

“I played a really good match,” said the winner who missed much of 2010 after a wrist operation. “I served much better than before. This is what I need if I want to beat top 10 players.”

Spain’s sixth-seeded David Ferrer stopped the progress of Indian Somdev Devvarman 6-4, 6-2 while South African Kevin Anderson beat Spain’s Pablo Andujar 6—2, 6—3.

Wimbledon marathon man John Isner ended the dream for American journeyman Alex Bogomolov with a 6-2, 7-6 (7-4) result. Bogolomov had made a mark 48 hours earlier by beating Andy Roddick, the second unknown American to defeat the Scot in as many events.

Compatriot Mardy Fish, seeded 14th and without a result to boast of in Miami, beat Richard Gasquet of France 6-4, 6-3.

Fish is now the highest-ranked home player left in contention after holder Andy Roddick was upset in his opening match and was set to drop from the top 10 next week.

On the women’s side, Kim Clisters and Vera Zvonareva led a sweep of women’s seeds into the fourth round with number two Clijsters recovering for a defeat of Spain’s Maria Martinez Sanchez 4-6, 6-4, 6-3.

The third-seeded Zvonareva, losing finalist at Wimbledon and the US Open, beat Australian Jarmila Groth 7-6, (7-4), 6-2.

There were also third-round wins for French Open champion Francesca Schiavone, the number five, who beat Spain’s Llourdes Dominguez Lino 6-4, 7-6 (7-2) and number nine Agnieszka Radwanska as the Pole put out Maria Kirilenko of Russia 7-6 (7-2), 6-3.

Victoria Azarenka, seeed eighth, needed to fight back to get past Slovak Domenika Cibulkova 3-6, 6-3, 6-4.

The 15th-seeded Frenchwoman Marion Bartoli, losing finalist a week ago in the Indian Wells final, accounted for Ekaterina Makarova with the loss of just two games.