At the Net: Young guns chip away at old guard

Philadelphia, PA ( - Sure, Novak Djokovic and Roger Federer are still in contention for another Wimbledon title, but fellow greats Rafael Nadal, Serena Williams, Andy Murray, Maria Sharapova, Li Na and Victoria Azarenka are not.

The men's final has not yet been established, but it's quite possible that no member of the "Big Four" (Djokovic, Federer, Nadal, Murray) will make the trip into Sunday's lucrative affair. We already know that the French Open king and U.S. Open champion Nadal and 2013 Wimbledon winner Murray won't be there.

Over on the women's side, only 2011 Wimby champ Petra Kvitova and 20-year-old rising Canadian star Eugenie Bouchard can decide that titlist, as no member of the ladies' "Big Four" (Serena, Maria, Azarenka, Li) managed the deep runs this year at the All England Club.

Back over to the men.

It is also quite possible that two members of the Big Four -- the former champion Djokovic and seven-time winner Federer -- could ultimately square off in the finale and restore some of the order that seems to have been lost in southwest London. But let it be known that youth has most certainly been served.

We've been waiting for the likes of Bulgarian Grigor Dimitrov and Canada's Milos Raonic to break through, and maybe that's finally happening now.

The gifted 23-year-old Dimitrov reached his first-ever Grand Slam semifinal by pasting the defending champion Murray in straight sets this week, while Raonic also punched his ticket to his first-ever major final four by sneaking past fellow young gun Nick Kyrgios in the quarters at the famed AEC.

Kyrgios is another rocket on the rise, as the 19-year-old Aussie slugger posted the upset of the fortnight by tackling the current world No. 1 and two- time Big W champion Nadal earlier this week.

The 6-foot-4 Kyrgios officially joined Dimitrov and the 6-foot-5 Raonic as the future of men's tennis. Dare I say the new "New Balls." Remember that campaign?

In the depleted women's draw, the U.S. Open champ and five-time Wimbledon titlist Serena was shocked by France's Alize Cornet in Week 1; the French Open champion and former Wimbledon winner Sharapova succumbed to German lefty Angelique Kerber in the fourth round; the Aussie Open titlist Li gave way to Czech Barbora Zahlavova Strycova in Round 3; and Azarenka, although still a bit rusty after returning to action just two weeks ago following a three-month foot-injury layoff, didn't get past Serb Bojana Jovanovski in the second round.

All of this means three of the four heavyweights were already gone before Week 2.

Bad for business?

You betcha.

Don't look now, but the mighty Serena has failed to reach the quarterfinals at four of the last five Grand Slam events. And don't forget she'll turn 33 in September.

When the smoke cleared at the semis in this year's third Slam, the women's final was left without any of its top stars ... but it just might be time for the new ones.

Bouchard is the only woman to appear in all three Grand Slam semis this year, while her semifinal victim at Wimby, 22-year-old French Open runner-up Simona Halep, is the only other woman to land in at least the quarterfinals at all the majors to this point in 2014.

The uber-confident Bouchard is also the first-ever Canadian player - male or female - to reach a Grand Slam final. How 'bout that!

Bouchard and the 23-year-old Raonic also have combined to give Canada two semifinalists at the same Slam for the first time. What's goin' on, U.S. players?

Does all of this mean the days of dominating are through for Nadal, Serena, Djokovic, Sharapova, Federer, Azarenka, and Murray? Maybe not just yet, but it's only a matter of time before some new Big Fours are established with the help of Dimitrov, Halep, Raonic, Bouchard and Kyrgios, none of whom is over 23 years of age.

Old guard beware.