After a day of bad weather, the US Open benefited from sunny skies in New York and all courts were filled with action on the first Friday of the tournament.

Djokovic Advances After Youzhny Retires

It has been a strange first week for top-seed Novak Djokovic. After defeating Jerzy Janowicz, he received a walkover in his second-round match and on Friday, leading 4-2 against Mikhail Youzhny, the Russian was forced to retire with a leg injury.

Youzhny had his thigh taped during the changeover trailing 1-4 but could only continue for one more game.

“I don't think I ever had this situation in my career,” Djokovic said afterward. “Obviously, I wish Mikhail a speedy recovery. I think he carried the injury into this match, that's what he said. I'll try to get the positives out of these six games. I did start with good intensity so I'll try to carry this into the next round.”

Sock Dispatches Cilic

Jack Sock and Marin Cilic played a dramatic 5-setter in a Davis Cup tie in July. In that match, Sock stormed back from a 2-set deficit to win. And given the level in which the Croat had been playing, there was a reason to think there might be another battle in store on Friday. But that was not the case as Sock dismantled Cilic 6-4, 6-3, 6-3.

Cilic entered the US Open as one of the dark horse contenders but it was Sock executing behind his strong serve. His first strike was a massive weapon as Cilic never saw a service break opportunity. Meanwhile, the American broke his opponent 4 times during the match.

“My first time in the fourth round here,” Sock said. “It was a big match for me, a big goal of mine. There's nothing better than playing in front of the home crowd here in New York. I put it out there on the line on every point.”

Sock will face ninth-seed Jo-Wilfried Tsonga in the next round. The Frenchman defeated Kevin Anderson in straight sets on Friday.

Dramatic Comeback for Keys

The third-round match appeared lost for American Madison Keys as she faced a 1-5 deficit in the third and deciding set against Naomi Osaka. But somehow, she stormed back to take the set and the match, 7-5, 4-6, 7-6.

The match featured two of the young, power players on the WTA tour. And both exhibited their big shot making during the match.

Keys took the first set and looked to be in control but in the second set, the 19-year old was broken, giving Osaka a 5-4 advantage. She would even the match on her racket.

Then, the wheels fell off for the American who dug what looked to be an insurmountable deficit. But, amazingly, she fought back, chipping away at her opponent’s lead. Osaka was reduced to tears as her big lead slowly slipped away. Eventually, the set would be decided in a tiebreak, but the momentum was on the side of Keys who closed it out.

“I just knew that if I stayed in the match that I could maybe have a chance to come back and get back in it,” Keys said. “The crowd today was amazing, and getting to play at your home slam on Ashe is a feeling like you can't even describe.”

The aggressive hitter struck 37 winners and overcame her 41 unforced errors in the match. She will meet Caroline Wozniacki in the fourth round in what will be a match between two players with very contrasting styles.

Nadal Cruises

Rafael Nadal set the tone early and cruised past Andrey Kuznetsov in straight sets, 6-1, 6-4, 6-2. The Spaniard showed more of his old form in the match that lasted just over 2 hours.

Nadal was successful from all spots on the court as his movement made it difficult for Kuznetsov. Meanwhile, he attacked his opponents serve and while it was not his best night serving, it was solid enough to maintain control throughout most of the match.

The 2-time US Open champion’s level of play has continued to progress in the first week of the tournament and clearly, his confidence, particularly from his forehand wing, is coming back.

Nadal will face 24th seed Lucas Pouille on Sunday in the fourth round.

Kerber Impressive in Victory

2nd-seeded Angelique Kerber gave a clinic in Arthur Ashe Stadium against Catherine Bellis. The German cruised to a 6-1, 6-1 victory.

CiCi Bellis is no stranger to big matches at the US Open as just two years ago, she upset Dominika Cibulkova in the first round as a 15-year old. But on Friday, she got more than she bargained for as Kerber controlled the match from the baseline and with her superior movement.

Kerber’s deep, heavy forehands overpowered the young American who spent most of the night chasing from a defensive position. And despite a crowd who were firmly behind her, she could not stop the assault from the world no. 2.

Meanwhile, Kerber continues the pursuit for her second slam of the year and her hopes to assume the top spot in the world rankings. She will meet Petra Kvitova next.