Mardy Fish avenged his Delray semifinal loss today. Fish toppled Juan Martin Del Potro in 7-5, 7-6 to qualify for his first quarterfinal at the Sony Ericsson Open.

Following steady play from both competitors, Fish was the first to get a break point in the eighth game of the initial set. Del Potro blotted that out to level the set at 4 all.

In the subsequent game, Del Potro had five break points but failed to capitalize. Perhaps a tad disappointed, Del Potro found himself in a love-40 hole. However, the Argentine dug himself out and drew even with Fish.

Yet, serving to extend the first set to a tiebreaker, Del Potro got down double break point and could not recover. As such, Fish banked the first set.

In the second set, Fish seized a break to go up 3-2. But, Del Potro rebounded quickly and erased the deficit. With neither man surrendering another service game, the second set went to a tiebreaker.

Fish sprinted to a 5-0 lead in the tiebreaker. Although Del Potro narrowed the gap to 6-5. On his third attempt at match point, Fish converted.

Fish was content with his play “it was one of those matches that a couple points here and there and you lose the match. . . He had a ton of break points. I had a few and converted on two of them; he got me on one. . . It was high quality tennis for the better part of it, I think. I’m sure he came off thinking he played pretty well and I played great”.

With Andy Roddick unable to defend his finalist status at Indian Wells from 2010 and his 2010 title in Miami, Roddick will drop out of the top ten. Consequently, if Fish advances to the semifinals, he will become the top ranked American. Fish is currently at number fifteen.

Fish’s view on the prospect of a career high ranking and being ranked higher than Roddick for the first time: “I feel coming through with Andy and the career that he’s put together. . .it would probably be pretty tough to still feel like I was the No. 1 American”.

Moreover, Fish said “[Roddick’s] career can be put on top of mine fifteen times. He’s won so many more matches, so many more tournaments, so many more Davis Cup matches. So, I don’t think I would ever feel like the No. 1 American. Even if I were to win tomorrow, the number next to my name would be smaller than his”.

After the match, Del Potro said “it was a nice tournament for me. [When I was out], I really missed the fans. They help me to fight for every match and I hope it will be the same in the future”.

Del Potro and Fish are more than competitors on court, they are friends off court. Del Potro cited “I’m very glad for his win today”.

Fish will battle David Ferrer for a place in the semifinals. Ferrer thumped compatriot Marcel Granollers in the fourth round 6-1, 6-2. Ferrer last reached the semifinals in Miami in 2005 and 2006.

Fish and Ferrer split their prior six meetings. Their last encounter was in 2007 at the ATP Masters series in Paris.

While Fish was successful, John Isner was not as fortunate. Despite a 3-1 mark against Kevin Anderson, Isner went down in straight sets 6-3, 7-6. Anderson will face either Viktor Troicki or Novak Djokovic who play later.

While Anderson and Troicki have never met, Anderson upset Djokovic as the defending champion in 2008 at the Sony Ericsson Open.