NEW YORK -- On this evening, certainly, Roger Federer was back to his old self.

Back to beating Robin Soderling and back to being a Grand Slam semifinalist -- two things he used to do as a matter of course.

Treating the whipping wind and his familiar foe as only slight nuisances, 16-time Grand Slam champion Federer served his way to a convincing 6-4, 6-4, 7-5 victory over the fifth-seeded Soderling in the U.S. Open quarterfinals Wednesday night.

"I've been practicing my serve a whole lot, for my whole career. If I can't serve in the wind, I've got a problem, you know?" said Federer, who had an 18-2 edge in aces against the big-hitting Soderling. "You could probably wake me up at 2 in the morning or 4 in the morning, and I could hit a few serves." Novak Djokovic reached the U.S. Open semifinals for the fourth consecutive year. Andrew Burton/Getty Images

Federer mixed speed with pinpoint placement, keeping two-time French Open runner-up Soderling guessing on returns.

"I always expect Roger to play well and serve well," Soderling said. "He served really well. He was brushing the lines a lot with his first serve, which is not easy when the weather is like this. He did that really well; much better than me."

Federer is 13-1 against Soderling. The lone loss was in their previous match, in the French Open quarterfinals when Soderling Federer's streak of reaching the semifinals at a record 23 major tournaments.

Federer then lost in the quarterfinals at Wimbledon, prompting some to question whether his best days were behind him. But now, a month after his 29th birthday, he is back in the semifinals at a Grand Slam tournament -- one that he has won five times.

Federer has won 45 of his last 46 matches in Flushing Meadows, the one exception the 2009 final against Juan Martin del Potro.

The second-seeded Federer will meet third-seeded Novak Djokovic in Saturday's semifinals. It's the fourth consecutive year they'll play each other in New York; they met in the 2007 final and then the 2008-09 semifinals -- and Federer went 3-0.

"You never know what's going to happen," 2008 Australian Open champion Djokovic said after beating 17th-seeded Gael Monfils of France 7-6 (2), 6-1, 6-2 earlier Wednesday. "I don't want to think about those losses in the last three years, which were really, really close."

All of the day's matches were filled with wind that gusted at up to 30 mph, sending all sorts of debris -- brown napkins, plastic bags, players' towels -- rolling on the court like tumbleweed, forcing points to be stopped and repeatedly making players catch their ball tosses.

"When it gets windy, I don't struggle much," Federer said. "I don't panic."

The last time Federer and Soderling played was on a dreary, rainy day in Paris, and the 6-foot-4 Soderling -- he's three inches taller than Federer -- used his strong forehand and serve to great effect, driving winners through the thick weather and pounding 14 aces.

On Wednesday, in contrast, Soderling didn't hit his first ace of the evening until the 143rd point of the match, nearly 1½ hours in, earning a smattering of sarcastic cheers from some fans in the sellout crowd of 23,718. By that time, Federer already had 15 aces, including three in a row in one game.

The wind affected shots, pushing behind a player's back at one end of the court and blowing into his face at the other. How big a deal was it? Instead of opting to serve when he won the pre-match coin toss, Federer selected which side of the court he wanted to start on, choosing to have the wind behind him for the first game.

"He can play really well in the wind," Soderling said. "He moves well. He's always in the right place."

Soderling chose to serve first, against the wind, and when they switched sides after that game, he earned three break points. But Federer saved each of them, the last with an ace at 120 mph, and held to 1-all. Soderling appeared to get rattled in that game on the first break point, when Federer challenged a call and got it overturned on replay review. Soderling wanted the point replayed, but the chair umpire awarded the point to Federer. Soderling argued, to no avail.

Soderling got a fourth break chance in the sixth game but let that slide by pushing a forehand long. From there, Federer won the next 15 consecutive points on his serve, including 10 in a row in which Soderling didn't even manage to put the ball in play with a return.

At 3-all, 30-15, Soderling blinked first. He missed a backhand and then a forehand, giving Federer his first break opportunity. And Federer made good with a fantastic drop shot that simply died on the court, ending a 12-stroke point and making it 4-3.

After an early trade of service breaks in the second set, Soderling again had a lapse at 2-all. Ahead 40-0 on his serve, he badly missed what should have been an easy overhead, putting it in the net. He lost the next five points to get broken -- and was never again in that set.

Soderling appeared to get himself back into the match by breaking for a 5-3 lead in the third set when Federer sailed an inside-out forehand wide on a 13-stroke exchange. The intrigue there lasted for all of a minute or so, because Federer broke right back to 5-4, helped by three consecutive errant forehands by Soderling.

At 5-all, Federer used the wind in his favor, taking a strong forehand approach shot by Soderling and hitting a hard, slice backhand lob. The shot curled over Soderling and floated down near the baseline. Soderling got there, but his forehand went long.

That helped Federer get two more break points, and he converted the second when Soderling yanked a backhand wide.

All that was left for Federer to do was serve out the victory. He did. And he finished, appropriately, with a pair of aces.

"I was able to pull away," Federer said, "and close it out quickly."

Djokovic managed to figure out how to deal with the swirling wind that topped 20 mph, choosing tactics wisely -- he won the point on 40 of 59 trips to the net -- and never allowing Monfils back into the match after a tight first set.

"It might be the case that [I've] developed," the 23-year-old Serb said. "Over time, you get experience playing in the different conditions, different situations."

He adjusted Wednesday, and he didn't let the wind bother him nearly as much as Monfils did. It was Monfils, after all, who tried to get too fancy in the match's fourth game.

As a ball headed toward him, Monfils jumped and brought his racket around his body and through his legs, when a regular swing would have sufficed. His attempt at a trick shot -- a variation of one Federer hit for a winner against Djokovic in the 2009 semifinals at Flushing Meadows -- landed in the net.

"I thought, 'Please, don't make it,'" Djokovic said. "I have been experiencing that too many times."

Clearly, the guy some call "The Joker" is still in possession of his well-known sense of humor.

Monfils, meanwhile, was not amused one bit by how hard it was to handle the wind, which kept changing directions and carried shots this way and that.

"I was completely lost," Monfils said. "Can't serve. Can't really use my forehand. You run for what?"

Djokovic was down an early break in the first set against Monfils but kept attacking and eventually broke back and then was solid in the tiebreak.

And that, pretty much, was that.

After one lengthy point won by Djokovic, his father stood up to applaud, showing off the black T-shirt he's been wearing with Novak's likeness on the front.

The younger Djokovic was asked after his match about Dad's fashion statement

"I would never wear the shirt. Me, personally -- never. My father? I understand. OK. He's proud. But me? Never," Djokovic said with a smile, adding: "I don't like myself that much."

Information from The Associated Press was used in this report.