Dominika Cibulkova of Slovakia, nicknamed the Pocket Rocket, finished off Victoria Azarenka on Sunday after twice previously having her against the ropes.  PARIS — The weather changed at the French Open, and the top of the tennis pyramid shook.  On court at the same time, the women’s No.1 seed, Victoria Azarenka, and the men’s No.1, Novak Djokovic, both found themselves in big trouble on different parts of the grounds at Roland Garros. Azarenka was down a set and a break against Dominika Cibulkova of Slovakia on the Suzanne Lenglen Court. Meanwhile, on the Philippe Chatrier Court, Djokovic was on his way to trailing by two sets to Andreas Seppi of Italy.  Inside the stadiums — with fans bundled up in sweaters and overcoats on this overcast, windy day — there were roars and gasps and occasional boos. Outside the stadiums, there were fans gathered in front of the electronic scoreboards and big video screen in the Place des Mousquetaires.  But in the end, only the top of the women’s pyramid would crumble in this fourth round. Cibulkova managed to finish off her upset of Azarenka, 6-2, 7-6 (7-4), but Djokovic would find a way to keep his French Open hopes alive by reeling in Seppi 4-6, 6-7 (5-7), 6-3, 7-5, 6-3.  The victory required four hours and 18 precious minutes of Djokovic’s time and energy. He had his serve broken six times and finished with 77 unforced errors to go with 45 winners: an edgy performance that bore scant resemblance to those in his opening matches here or to those in 2011, when he was in the form of his life.  But the essential is that he is now just three victories away from becoming the first man since 1969 to hold all four of the Grand Slam singles titles.  “You know, I’m not worried,” Djokovic said. “I’m just hoping I can wake up tomorrow, knowing that I’m in a quarterfinal, and I just want to deliver my best performance in the next challenge, forget this match today, take the best out of it. I’m proud that I’ve been fighting and coming back from two sets down. That’s all I can say now.”  Djokovic — now 16-5 in five-set matches — will next face the winner of the Sunday match between Jo-Wilfried Tsonga and Stan Wawrinka. After that Djokovic could face his longtime rival Roger Federer in the semifinals. Federer had a pyramid-rattling moment of his own on the Lenglen Court on Sunday as he lost the first set to David Goffin, a 21-year-old lucky loser from Belgium who looks younger. Goffin has idolized Federer since childhood and was playing him for the first time and also playing in his first Grand Slam tournament.  It had to have been surreal after watching Federer for so long on screens to suddenly see him across the net at Roland Garros: that familiar whipped forehand, that sliced one-handed backhand, that shake of the head (and hair) between points. But Goffin also got to see Federer’s pursed lips and furrowed brow as he answered the Swiss champion’s spin and artistry with plenty of legerdemain of his own.  Goffin conjured touch volleys, surprise forehand winners on the round and even a drop volley winner to end a point full of improvisation in the fourth and final set that earned him a standing ovation from the crowd. He responded by grinning and bowing three times.  When it ended with Federer winning, 5-7, 7-5, 6-2, 6-4, French Open officials broke protocol by interviewing both the winner and loser on court side by side. “I won’t hide from you that I had photos of Roger all over my room,” Goffin told the crowd.  It was a terrific moment and Federer, a 16-time Grand Slam singles champion soon to turn 31, handled it graciously, encouraging the youngster to speak with him in the locker room. “You shouldn’t be shy with me,” he said. “I think I’m one of the most relaxed former No.1’s on tour.”  Interviews over, the two men gave the crowd what it had been chanting for and embraced, but Federer, who will face Juan Martín Del Potro or Tomas Berdych in the quarterfinals, has less lighthearted moments ahead. He has already dropped a set each to three players ranked well below him.
Victoria Azarenka, the top-ranked womenâs player, fell Sunday to Dominika Cibulkova, who had twice been on the verge of knocking out Azarenkaâs defenses in the past two years.