Isner unable to conjure up another upset

Whatever magic it was that John Isner had while upsetting fifth-seeded Andy Roddick on Saturday was gone by Monday.

Isner’s big serve and attempts at volleys couldn’t dent the solid defense of Spain’s Fernando Verdasco. So as quickly as it took the 24-year-old Isner to lose to the 10th-seeded Verdasco, 4-6, 6-4, 6-4, 6-4, that was as long as it took to come up with this fact:

For the first time in the open era of tennis there will be no American men in the quarterfinals of the U.S. Open.

But 17-year-old Melanie Oudin did her part in pumping U.S. fans full of hope. The unseeded Oudin, from Marietta, Ga., eliminated a fourth consecutive higher-ranked Russian with her 1-6, 7-6 (2), 6-3 win over 13th-seeded Nadia Petrova.

Next up for Oudin -- not another Russian. Ninth-seeded Caroline Wozniacki of Denmark upset sixth-seeded Russian Svetlana Kuznetsova, 2-6, 7-6 (5), 7-6 (3), in a 2-hour 23-minute fourth-round match. Kuznetsova’s loss means this is the first time in the last 29 majors that no Russian has reached the quarterfinals.

And as usual top-seeded Roger Federer floated above it all, leaving 14th-seeded Tommy Robredo hardly even tired even after he lost, 7-5, 6-2, 6-2. Fourth-seeded Novak Djokovic won the last match of the night, 6-1, 6-3, 6-3, over 15th-seeded Radek Stepanek.

And even Federer is impressed with Oudin. Federer, the five-time defending champion, said he has enjoyed watching her sudden emergence.

“She’s beaten great players on the way,” Federer said. “It’s nice for a change that somebody’s coming up we haven’t heard about before.

“If they make a breakthrough, it’s not much of a surprise . . . because we had 14-, 15-, 16-year-olds making a breakthrough. This is very exciting and very much needed on the women’s side.”

Stat of the day

Kuznetsova had 59 winners and 63 unforced errors in her loss to Wozniacki, who had 16 winners and 25 unforced errors -- a crystal clear indication of who was aggressive and who was defensive.

Upset of the day

Oudin has dibs on this spot, this time for beating Petrova.

Quote of the day

Isner on his schedule this fall when the ATP Tour moves to Asia: “I’ve never been to Asia ever, so I’m going to have three weeks over there. I like staying at home and watching football. But I’ve got to be over there and not watching football.” Spoken like the former University of Georgia student he is. But not exactly like a committed tennis professional.

Today’s featured matches

In Arthur Ashe Stadium, beginning at 8 a.m. PDT, top-seeded Bob and Mike Bryan play Aussies Carsten Ball (who lives in Newport Beach) and Chris Guccione in men’s doubles, followed by 18th-seeded Li Na of China against Kim Clijsters and second-seeded Andy Murray vs. 17th-seeded Marin Cilic. The night session, beginning at 4 p.m. PDT, features No. 2-seeded defending champion Serena Williams against 10th-seeded Flavia Pennetta and third-seeded Rafael Nadal vs. 13th-seeded Gael Monfils.

Out and about and around the grounds: At Louis Armstrong Stadium, beginning no earlier than 1 p.m. PDT, seventh-seeded Jo-Wilfried Tsonga of France faces 11th-seeded Fernando Gonzalez of Chile.

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diane.pucin@latimes.com

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