US Open Tennis 2015 Results: Early Saturday Results, Highlights and Scores

Championship contenders Roger Federer and Petra Kvitova both advanced to the fourth round of the 2015 U.S. Open during Saturday's early action. Johanna Konta also continued her surprise run with a victory over Andrea Petkovic to reach the second week. 

After a drama-filled start to the tournament, with several high-profile upsets and numerous retirements, some stability is starting to return to the USTA Billie Jean King National Tennis Center grounds. That said, another player did withdraw, as Jiri Vesely couldn't complete his match against John Isner.

Let's check out a complete list of scores from the afternoon session in New York. That's followed by a recap of some key storylines from Day 6 of the season's final major.

Early Saturday Results

Men's Results	Score
Women's Results	Score
(2) Roger Federer def. (29) Philipp Kohlschreiber	6-3, 6-4, 6-4
(6) Tomas Berdych def. (31) Guillermo Garcia-Lopez	6-7, 7-6, 6-3, 6-3
(12) Richard Gasquet def. (24) Bernard Tomic	6-4, 6-3, 6-1
(13) John Isner def. Jiri Vesely	6-3, 6-4, Ret.
Donald Young def. (22) Viktor Troicki	4-6, 0-6, 7-6, 6-2, 6-4
(5) Petra Kvitova def. (32) Anna Karolina Schmiedlova	6-2, 6-1
(20) Victoria Azarenka def. (11) Angelique Kerber	7-5, 2-6, 6-4
(22) Samantha Stosur def. (16) Sara Errani	7-5, 2-6, 6-1
Johanna Konta def. (18) Andrea Petkovic	7-6, 6-3
(26) Flavia Pennetta def. Petra Cetkovska	1-6, 6-1, 6-4
Varvara Lepchenko def. Mona Barthel	1-6, 6-3, 6-4

Day 6 Recap

Federer came into the tournament on a high note after winning the warm-up event in Cincinnati, which featured wins over Andy Murray and Novak Djokovic. He's maintained that high level of play during the early stages of the U.S. Open.

The No. 2 seed has reached the fourth round without dropping a set after dispatching Philipp Kohlschreiber in straights. The five-time champion in New York now holds select company as one of the players with 75 match wins in the tournament, per ESPN Stats & Info:

Next up for Federer is Isner, the top-ranked American. He's also breezed through the first three matches without losing a single set. He found himself in firm control against Vesely on Saturday before the Czech rising star decided to call it quits.

As mentioned, although the rate of players retiring from matches has slowed in recent days, it's still been one of the event's key talking points. ESPN Tennis provided some further context about just how bad it's become during Week 1:

"

Vesely's retirement (to Isner) is 14th of the men's event, 16th overall of the tourney, the most retirements at ANY Major in the Open Era.

— ESPNTennis (@ESPNTennis) September 5, 2015"

There are numerous reasons for the problem, ranging from the grueling schedule to players wanting to collect their first-round money. The bottom line is, it hurts the event as a whole when so many players are unable to perform at a high level.

One other noteworthy result in the men's draw came from Donald Young. The American, who's gone through more ups and downs by age 26 than some players do in a career, fought back from two sets down to upset Viktor Troicki. His play over the final three rounds was electric at times.

U.S. Open Tennis showcased the celebration:

On the women's side, Kvitova is playing well enough to believe she could seriously challenge Serena Williams if they were to both reach the title match. The Grand Slam hopeful can't look past Madison Keys after struggling to pull away from another American, Bethanie Mattek-Sands, on Friday.

The Czech lefty completely dominated No. 32 seed Anna Karolina Schmiedlova, striking 29 winners and six aces, compared to just 10 winners and one ace for her opponent. She's one of the few who can at least come close to matching Williams' power.

It certainly seems like she's playing with a lot of confidence and a high comfort level, which shined through during her post-match press conference, per WTA Insider:

Now it will be intriguing to see how she handles Konta. The unheralded qualifier from Great Britain is already riding a wave of momentum after two straight wins over ranked opponents in Wimbledon finalist Garbine Muguruza and, on Saturday, Andrea Petkovic.

Konta didn't play highlight-reel tennis against Petkovic. She finished with more double-faults than aces and more unforced errors than winners. That said, she chases down a lot of shots, keeps points alive and forced opponents into mistakes. If Kvitova has an off day, things could get interesting.

Regardless of the result, it's been a tremendous run, as Piers Newbery of BBC Sport detailed:

Perhaps the day's most intense clash came courtesy of Victoria Azarenka and Angelique Kerber. It's a matchup more fitting for a quarterfinal or semifinal, and it certainly felt that way as they battled back and forth throughout three sets.

Eventually Azarenka pulled away in the third set and managed to close it out after some tense moments. She's another player on the opposite half of the draw who could make a run toward the final, which she reached in this tournament in both 2012 and 2013.

U.S. Open Tennis highlighted match point after the extended battle:

A few more big names will be in action during the night session. Simona Halep, the second seed on the women's side, takes Arthur Ashe Stadium first to face Shelby Rogers. It's a match Halep should win, but the young American could get the crowd behind her with a strong start.

That's followed by third-seeded Andy Murray taking on Thomaz Bellucci. Murray is coming off a narrow five-set escape against Adrian Mannarino and will need to raise his level of play considerably to rebound and make a deep run in the event.

Stan Wawrinka, Kevin Anderson and Sabine Lisicki are among the other notable players with scores still to settle around the grounds as day turns to night in New York.

All statistics courtesy of USOpen.org unless otherwise noted.