U.S. Open Day 9: Wozniacki destroys Errani; Federer cruises; Cilic survives; Monfils bounces Dimitrov

After nine days at the U.S. Open, the men's quarterfinals are set. Meanwhile the women, on an expedited schedule, have one of their semifinal matches locked in, with the next to be decided when their four remaining quarterfinalists square off on Day 10.  

Here's what went down on Tuesday Flushing Meadows: 

Wozniacki blasts Errani to make first Slam semi since 2011

It's been a long time since Caroline Wozniacki has looked as dominant as she did on Tuesday night. Even back when she was holding down the World No. 1 seed for 49 straight weeks, you didn't see her hitting with the the pace, the confidence, the gusto that she showed in her quarterfinal match against Sara Errani. 

On a windy night inside Arthur Ashe stadium, Errani, who doesn't hit with much power to begin win, looked flustered and helpless from the start. Wozniacki ran down everything tossed at her, and ate up Errani's slow-rolling spin serve, which topped out at 85 mph and came in at an average of 76. The 13th-seeded Italian, who usually compensates for her lack of power with speed, craftiness and guile, didn't hold serve once. In fact, she won just eight service points all match. Eight.  

Wozniacki was somehow both patient and aggressive, picking her spots and staying within herself, but dictating points and using the entire court, especially while unloading on her pattented backhand. She was never in danger, winning 6-0, 6-1 in 55 minutes. This was probably the most dramatic thing that happened all match: 

[Courtesy CJ Fogler] 

With the win, Wozniacki is into her first Grand Slam semifinal since 2011. It's clear this is her favorite major; of her five career Slam semis, four have now come in New York, including her one finals appearance - as a 19-year-old back in 2009. 

She'll have a great chance to repeat that feat in 2014. Her semifinal opponent is unseeded Peng Shuai, against whom she has a 5-1 record, and last lost to in 2007. 

Federer, Berdych fly into quarters on autopilot 

Roger Federer has done little so far to dispel the chatter that this U.S. Open could be the tournament that yanks him out of his 2-plus-year Grand Slam drought and puts him back on top of the men's tennis world. 

In the fourth round, the five-time U.S. Open champ routinely picked apart 17-seed Roberto Bautista Agut. He kept the points short, moved as swiftly as the Federer of old, let hardly anything get past him, bull-rushed the net and volleyed brilliantly. It was clean, smart, mistake-free tennis, and it was totally devoid of suspense. In the end, Federer walked off with a 6-4, 6-3, 6-2 victory to coast into the U.S. Open quarters for the 10th time in the last 11 years. 

No. 6 Tomas Berdych was, if possible, even more dominant than Federer. Playing 20-year-old upstart Dominic Thiem, who came in having won six straight sets against two seeded opponents, Berdych was ruthless in his service game, winning 85 percent of his first-serve points, and saving all seven break points he faced. 

His return game was equally impressive, as he feasted on Thiem's second serve, winning 69 percent of those points, and converting five of his nine break points. He finished Thiem off 6-1, 6-2, 6-4 in a cool hour and 38 minutes. His opponent was duly humbled.

Berdych also won his third-round match in an hour and 49 minutes, which means he's spent less time on court in his past two matches than his quarterfinal opponent, Marin Cilic, did on Tuesday alone. 

Speaking of which...

Cilic outlasts Simon in 5

The long matches are supposed to favor the little guys. Sure, the great, hulking behemoths of men's tennis can leverage their vantages into blistering serves that dive straight down and rocket out of reach, or punch back would-be passing shots thanks to arms that span the doubles alleys. 

But after four hours of dragging those great, hulking frames around the court, the odds tend to tilt out of their favor. (Even battling foot injury, 5-foot-10 Kei Nishikori looked far spryer than 6-foot-5 Milos Raonic in the fifth set of their fourth-round marathon Monday night.) 

Marin Cilic, at 6-foot-6, has always been a bit of an outlier in this regard. He came into Tuesday's fourth-round tilt with No. 26 Gilles Simon with an 18-9 record in five-setters. (Some other classic tall guys, by comparison - Juan Martin del Potro: 4-9. John Isner: 5-12. Ivo Karlovic: 4-13.) 

Cilic needed every ounce of his anomalous stamina against Simon, as the latter kept pace for four grueling sets, taking the match the distance and pushing it past the four-hour mark - just the second match of the tournament to go that long (Raonic and Nishikori's was the first). ESPN ran a poll before the fifth set started asking who would win, and nearly 60 percent favored Simon. 

Apparently they forgot about Marathon Marin. The 14th-seeded Croat was in fine form in the decider, slapping 17 winners against 11 errors, dropping just seven service points, and winning 61 percent of the "medium rallies" (exchanges of 4 to 9 shots). 

In the end, Cilic outlasted Simon - who showed his fatigue in landing just 46 percent of his first serves in the fifth - and emerged with a 5-7, 7-6, 6-4, 3-6, 6-3 win. He's off to his third career U.S. Open quarterfinal, and, after also making the final eight at Wimbledon, his second straight at a Slam. 

Score one for the big guys!

La Monf takes down Ser Grigor

The enigmatic Gael Monfils rode an overwhelming service performance into the quarterfinals with a three-set victory over Grigor Dimitrov.

Monfils was hardly threatened on serve during the match, but did survive two sets points to win a second-set tiebreak and eventually emerged with a 7-5, 7-6 (8), 7-5 victory. 

Dimitrov, the tournament's No. 7 seed, was exceptional on serve as well, allowing just four break point opportunities, but he failed to save three of them. He bows out of the tournament in the fourth round, his best finish at Flushing Meadows. 

Into the quarters for just the second time at the U.S. Open, Monfils - who turned 28 yesterday - will have his hands full with a rested and in-form Federer. 

Peng dominates Bencic in first Grand Slam quarterfinal

The epic fourth-round matchup between Kei Nishikori and Milos Raonic may have spilled late into Tuesday, but Day 9 began in earnest with a pair of unseeded women looking to punch their ticket into the semis. 

China's Shuai Peng was undaunted by the stadium sounds of a Grand Slam quarter-final. The unseeded 28-year-old put forth a dominant performance in her first opportunity to crack the final four of a major, dispatching Switzerland's Belinda Bencic in straight sets 6-2, 6-1. This is Peng's 37th Grand Slam appearance. Only five women have participated in more major tournaments before getting to a semifinal.

Peng, who has yet to drop a set in the tournament, has knocked out three seeded women during her run to the semi, including No. 4 Agnieszka Radwanska in the second round.