Anyone know the three most popular letters at this year’s US Open? Nope. Not U-S-A. The three most popular letters are R-E-T. Jo-Wilfried Tsonga became the 10th retirement in the Men’s Singles Draw on Tuesday Night, unable to complete his Quarterfinal match with Novak Djokovic. Eerily, three of those 10 retirements have come from opponents of the World #1. Vesely retired before they ever even took the court in Round-2, Youzhny retired after 6-games in Round-3, and Jo-Wilfried retired at the start of the third-set on Tuesday night. Novak has advanced to his 9th consecutive US Open Semifinal having only played two complete matches. Crazy.
The day’s other Quarterfinals on Ashe saw Angelique Kerber and Gael Monfils easily advance, while Caroline Wozniacki reached her 5th US Open Semifinal after an early ankle-roll stalled Latvia’s Anastasija Sevastova. Over on Armstrong, Bob and Mike Bryan fell to Spaniards Feliciano Lopez and Marc Lopez…
 Angelique Kerber (GER) def  Roberta Vinci (ITA)
Final 7-5, 6-0. Six breaks in the first set. 12 unforced errors from Kerber before the second changeover. Eeek. Up 5-4, Roberta Vinci had the edge, serving for the set. Didn’t happen. Kerber leveled it with her third break of the opener, then held. Down 5-6, Vinci fell-behind 0-40, and lost the opener on a second-serve foot-fault. Frustrating.
Roberta had a fairy-tale run here in Flushing last year, defeating Serena Williams in the Semifinals to reach her first Grand Slam Final. She’d go-on to win her first Premier WTA title in St. Petersburg in February, and at 33-years-old became the oldest player on the WTA Tour to make her top-10 debut. She’s remained in the top-10 since, and came into the Open as the World #8.
Angelique has had an absolutely stunning 2016. After winning her first Grand Slam title at the Australian Open, she won her 9th WTA singles title in Stuttgart, reached the Wimbledon Final and earned Olympic Silver. She was a finalist in Cincinnati just a week before the Open. Her confidence is at an all-time high, and her sights are set on the World #1 ranking. A win on Saturday could get her there…
In set-2, Kerber pulled it together. At the first sit-down, she was 3-games away from the Semifinals. She played far more patiently than in the first, picked her points of attack, and drilled second-serve returns. Elevated errors from Vinci certainly didn’t hurt. By the second change-over, Angelique was a game away from the win. Why wait to serve it out? After a few trades of deuce in game-6, Kerber advanced with her 7th break, earning the win in 78-minutues. No doubt, another big confidence boost for the German.
Fun stat: Kerber had 22 unforced errors in the first set. In set-2? She had 3.
UP NEXT: Caroline Wozniacki (DEN)
 Lucas Pouille (FRA) vs  Gael Monfils (FRA)
Final 6-4, 6-3, 6-3. Three consecutive 5-setters, after a 1st-Round win in four. Lucas Poille won the biggest match of his career on Sunday, coming back from down a break in the 5th to defeat 2-time US Open Champion Rafael Nadal in a deciding-set tie-break. Before his second consecutive Grand Slam Quarterfinal, he’d spent 12-hours and 53-minutes on the court. Fitness.
Meanwhile, Gael Monfils cruised through the first four rounds without dropping a set. With only 7-hours and 50-minutes of match-play, he was clearly more rested than his fellow Frenchman. At 3-all in the first, Gael earned his first break, consolidated, then served it out 6-4.
The two played once before, in the first round of the 2015 Australian Open. Monfils won it in five; obviously Lucas hadn’t played 19-sets of tennis going-in. This was a different narrative.
With Monfils up a break, at 4-3 in the second, rain interrupted play on Ashe. While it took only a few minutes to close the roof, it still took 20-minutes to dry the courts. Momentum buster? Hardly. Gael served to go up 5-3, then Pouille handed-over the set with a double-fault at 0-40. Monfils was a set away from his second career Grand Slam Semifinal, his first Semifinal in eight-years.
In the third, Monfils ran away with it, jumping ahead 4-1 by the second change-over. He’d win it 6-4, 6-3, 6-3 in just over 2-hours.
UP NEXT: Novak Djokovic (SRB)
Caroline Wozniacki (DEB) vs Anastasija Sevastova (LAT)
Final 6-0, 6-2. Game-1 took 7-minutes. It was an anamoly. Two-time US Open Finalist Caroline Wozniacki opened with a break, then found herself up 3-0 at the changeover after Anastasija rolled her ankle right out of the gate. Nightmare. Sevastova immediately called for the trainer to retape her right ankle. It didn’t help. Anastasija simply couldn’t put points on the board. She had ZERO zip on her serve and favored drop-shots and slice over trading pace. 31-minutes in, Wozniacki was up a set.
At the beginning of set-2, Sevastova clearly didn’t want to be on the court. To say her body language was defeatist would be an understatement. Shoulders slumped, slowly strolling between points, reluctantly challenging…she was just going through the motions, playing hurt, little hope of discovering any rhythm. After 9-games, she was beyond frustrated, without a single game on the board. After a conference with the trainer, she got back on court to accept the beat-down.
Down 0-4, Sevastova got her first jolt. She finally held, with two huge serves at deuce. Fans wanted more, sending her to the changeover with the loudest roar we’d heard all night under the closed roof. But it was too little, too late. The ankle was still too tender. Three games later, we were done. Caroline Wozniacki advanced to her fifth US Open Semifinal in just 65-minutes.
UP NEXT: Angelique Kerber
 Jo-Wilfried Tsonga (FRA) vs  Novak Djokovic (SRB)
Final 6-3, 6-2, RET. Set-1’s fire-works came at 2-all, where Jo-Wilfried Tsonga scored the first break-point of the match. Novak immediately erased it, then returned from the changeover to earn triple break point. At 15-40, Jo-Wilfried threw-down a double-fault. Costly. Or so we thought. Remarkably, Tsonga answered with a break of his own, and we were back on serve; Djokovic up 4-3. In the next game, Tsonga fell behind again – 0-30, 15-40 – but got it to deuce behind two big first-serves. Two points later, Novak gained the edge, then closed-out set-1 on his own racquet.
After an extended Tsonga bathroom break, we were on to set-2 – the match just 38-minutes young. Both held, then Novak scored his third break before the first sit-down, and consolidated with a hold at love. Efficient, yes – but Tsonga was hobbled. Novak earned a fourth break to go up 5-2, Jo-Wilfried received a rub-down on his left-knee, then Novak served out the set.
That was all she wrote. Tsonga made the trip to the baseline to start set-3, but pulled the ripcord after one attempt at serve.
Novak Djokovic has advanced to his 9th consecutive US Open Semifinal having played only two complete matches. After the Vesely walkover in Round-2, Mikhail Youzhny retired after just six games in Round-3. Kyle Edmund was an easy 3-set dispatch in the Round of 16, while Tsonga quit after an hour and 21-minutes.
Losing to Juan Martin Del Potro in the First-Round of the Olympic Games was a heart-breaker. This run in Flushing has been an unexpected gift.
UP NEXT: Gael Monfils.
DAY-9 UPSETS AND INTRIGUING RESULTS
-  Feliciano Lopez / Marc Lopez (ESP) def  Bob and Mike Bryan (USA) 7-6(2), 4-6, 6-3. Tough loss for Bob and Mike. The Brothers haven’t won a Slam since earning thier 100th career title on Arthur Ashe Stadium two years ago.