Serena Williams of the U.S. reacts after defeating Kaia Kanepi of Estonia at the 2014 U.S. Open tennis tournament in New York, September 1, 2014.
Age: 33 Nationality: American Prize money: $11 million Endorsements: $11 millionOnce again, Serena Williams finished as the world no. 1 for 2014. She has endorsement deals with Wilson, Nike, OPI and Gatorade. She also holds equity deals with Sleep Sheets, HSN, Mission and the Miami Dolphins. REUTERS

Top seeded Serena Williams overcame the unforgiving heat to dispose Kaia Kanepi of Estonia in two impressive sets, 6-3, 6-3, to advance to the quarterfinals rounds of the 2014 US Open at Arthur Ashe Stadium.

Hardly showing any ill-effects of playing every day in the humid temperature, Williams displayed the form that no doubt puts her on top of the rankings in women's tennis. She is also deep in the rounds of the women's doubles draw with sister, Venus Williams and she targets to snatch both victories later this week.

"I never thought it would be so exciting [to advance to a quarterfinal]," she said. "It feels good. Obviously I don't want this to end. But I'm just happy that I'm able to be performing a little better at the end of the year."

According to the New York Times, Williams displayed her impressive serves registering 115 miles per hour that just zoomed by a shellacked Kanepi who could do nothing in retaliation returns. This was visible during the first set when consecutive serves zoomed by the Estonian without being able to swing back her racket. Her large frame shoulders and long limbs could do nothing to negate the speed aces of Williams.

"Yeah, I think her serve was really good," Kanepi said of Williams. "The whole match, she was really good. She returns the ball very fast."

Williams returned the favor saying that her opponent fought "incredibly hard." But that assessment is generous compared to the control game she displayed during the match. One reporter pointed out that statistics would show that the best women's player no longer covers the same length of court as she used to. She responded with a timid smile and said that at her age, she does not want to be running a lot and is dictating the position and trajectory of the ball.

William's win will mean that she will face veteran Flavia Pennetta of Italy next. The Italian also easily handled Casey Dellaqua in her own fourth round match, 7-6, 6-2 and set up the quarterfinals showdown with the American. If history is to be a guide, Williams holds the advantage as she has won five of their six last meetings. Despite this, the number one seed is not taking the Italian lightly. She acknowledges that the experience of Pennetta is major ace in the sleeve for the Italian.

For now, Williams is reveling in the fact that she just reached the first quarterfinals match for the year 2014 and has shoved the monkey on her back.