*After a day 9 of intermittent rain delays and postponements that threatened to throw a major glitch in US Open’s scheduling, day 10 concluded with order restored … except for a shocking upset.

Minor upsets have been a recurring part of this year’s topsy-turvy story Open story, but the business end of the tournament was still expected to include certain top seeds:

Men: Novak Djokovic; Roger Federer (SRB); Andy Murray (GBR); and David Ferrer (ESP) (replaces injured Raphael Nadal)

Women: Victoria Azarenka (BLR); Maria Sharapova (RUS); Serena Williams; and you’ve read the story about 2nd seeded Radwanska’s early exit.

On the women’s side, tournament officials can breath easy because the ratings-getters are still in it and are taking care of business.

Maria Sharapova outlasted a tough Marion Bartoli (FRA) in a three-set thriller that ended with a 3-6 6-3 6-4.

Victoria Azarenka knocked out defending champion Samantha Stosur (AUS) in a quarterfinal match that was worthy of a being the US Open final – if there wasn’t a such thing as a Serena Williams who is a fixture in such contests.  After an uninspired and nervous start by Stosur, who had never even won a set off the world no. 1 Azarenka, she found her groove late in the second set and pushed, with everything she had in her well-toned body, the match to a three-set blockbuster.  Both women were playing very high level and gutsy tennis on Ashe, but Azarenka eventually prevailed in a close third-set tiebreaker, 6-1 4-6 7-6(5).

Sharapova and Azarenka will meet next in the semis to battle it out for a spot in the final.

The surprise Italian face-off between best friends and doubles partners Roberta Vinci and Sara Errani ended with Errani besting her pal, 6-2 6-4, and reaching her first – and Italy’s first – US Open semifinal.  Eranni will next play Serena Williams.

And speaking of Serena Williams, while her potential opponents were battling it out with one another in their lead up matches, she was coasting through her draw with nary a threat.  After allowing Russian Ekaterina Makarova to get 4 games off of her, she went on a 24 game winning streak leading up to the match between she and Serbian Ana Ivanovic.

“She’s such good player and I knew I had to come out here focused,” Williams said of the match up.  “I think I played well … better than the first few matches.”

Ivanovic is surging a former world no. 1 and French Open champion, so there was a chance that she’d use her superior forehand to trouble Serena, but …  in under an hour, she served the Serbian out of Ashe Stadium with 12 aces, 26 winners and only 14 unforced errors. She’s never beaten Williams, the tournament’s favorite.

The tournament favorite on the men’s side had different fortunes, though.

On the morning of Day 11, we find the most consistent player of the ATP and arguably the greatest of all time OUSTED from the tournament.  In a night match held on Arthur Ashe, Czech Tomas Berdych gathered enough nerves to engage his full arsenal of tennis weaponry – big serve, lightning fast and heavy ground strokes and nimble feet – to evict he king from his throne.  It took four sets, but Berdych pulled out an incredible and astonishing win against the Swiss phenom.

Federer started the match with sluggish footwork and devoid of his usually mystifying power and accuracy.  Before the stunned fans realized it, he was down two sets and a break to the confident Czech … until Berdych realized the magnitude of his lead. That’s when the train went off the tracks and he couldn’t even buy a point. A nervous service game at 3 all gave Federer the break for 4-3 on serve and from there he did what any 17-time Grand Slam champ would do: put the pedal to the asphalt and didn’t let up until he was back in the match with the set and all the momentum under his belt. By then, the crowd was in a frenzy and any betting man would’ve put his money on Federer coming out victorious in five sets.

Didn’t happen.

A 4th set, seventh game hiccup gave Berdych a 5-3 lead on serve, to add to the two sets he had commandeered at the beginning of the match. With his composure regained from the 3rd set choke, he confidently served it out, 7-6(1) 6-4 3-6 6-3.

Federer’s untimely departure coupled with Nadal’s absence now leaves the door open for a breakthrough Grand Slam winner at this year’s Open.  Djokovic is the very capable defending champion, but his performance of late makes him vulnerable to defeat by any of the men remaining in contention.

Juan Martin Del Potro, a former US Open champion who sped along Andy Roddick’s retirement yesterday on Ashe in front of tearful fans, beating him (6-7(1) 7-6(4) 6-2 6-4), used to be a top five player, but soon after winning his first and only Slam, injuries took him out of the game for a long period.  Now that he’s back, he’s been threatening to find dangerous the form that he once had, his performance improving with each tournament, and can at some point capture another major title (he denied Djokovic a bronze medal at the London Olympics).

David Ferrer, the ultra consistent, but perpetual bridesmaid, has never been able to break through and even reach the final of a Slam because he’s just good enough to be seeded near the top, but usually has to get through Nadal and Federer, the latter whom he’s never beaten, to make it happen.  But with the two out, he could very well reach a new height in this career.

Andy Murray, who survived a scare by Croat Marin Cilic on Day 10 (3-6 7-6(4) 6-2 6-0), has the momentum going into the tournament after beating both Federer and Djokovic to secure the gold medal for Great Britain.  He had solved the Djokovic puzzle on a couple of occasions before, but It was his first time beating Federer and wasn’t guaranteed to repeat the feat at the US Open.  Now that Federer is out, who he was set to play next had Fed won, and Djokovic’s confidence being questionable due to recent losses, his chances of winning his first Grand Slam are increased exponentially.

Federer killer, Berdych, and Janko Tipssarevic are still in the draw, but chances are they will not have the fortitude to win the big prize; the other men are simply hungrier.

There are thrilling match ups set for the remaining several days of the tournament, so check here to get schedules, stats and other results.