Sara Errani in tears after second-round flameout at U.S. Open

Sara Errani blamed a case of nerves for her loss to Flavia Pennetta at the U.S. Open. (Timothy Clary/AFP/Getty Images)

NEW YORK -- No. 4 Sara Errani became the highest seed to fall at the U.S. Open, losing to Flavia Pennetta 6-1, 6-3 in the second round on Thursday.

Errani, who made the semifinals here last year, was in tears after the loss and admitted she struggled with the pressure of being a top-four seed. (Watch a portion of her news conference here.)

"For me, [it] was difficult," Errani said about the loss. "I think the worst thing was the fight. Normally [it] is my best thing that I do on the court, and today was not good."

Errani, ranked No. 5 in the world, was bumped up to the No. 4 seed after Maria Sharapova withdrew. A top-50 player for much of her career and long considered more of a doubles specialist (she holds the No. 1 spot in the doubles rankings with partner Roberta Vinci) Errani broke into the top 10 in 2012 after making a surprising run to the French Open final. The pressure of being a top player who, at least on paper, is expected to win, combined with the prospect of intense scrutiny that would come with a loss, was paralyzing for the diminutive Italian.

"I have never been here like this," Errani said of her seeding. "I have never been in this situation, so it's a new situation for me. We have to find the solution, because I think these things happen to everybody when you feel on top and you are there and people [are] playing against you with no pressure and you have a lot of pressure. I'm not that kind of player that can go there and make aces and winners, and if the ball is going in I'm doing good."

The loss will drop her out of the top five.

"For me, [the key] is to go there and fight," she said. "If I feel that I'm not fighting good [because I feel] too much pressure ... I don't want to go on the court. I don't want to go to play. I don't want to stay there on the court. I feel very bad. So that is the problem for me. I have to find the way to find the motivation to go there. If I go there and I know that if I lose [it] is very bad and if I win [it] is normal, [that] is not a good thing. I have to find a way to like to stay there and fight. That is important. I hope to find it."

Serena Williams sympathized with Errani's stress.