US Open Tips: Is this the end of Ivanovic?

Has Ana Ivanovic reached the end of the road?
We have eight fourth round matches at Flushing Meadows today with Abelson Info offering a selection in each and they're predicting an upset defeat for Ana Ivanovic...
Men's Tournament
Nicolas Almagro (11) v Tomas Berdych (6)
16:00 Louis Armstrong Stadium
H-to-H 3-7
This will be a real battle of the big hitters. It will be a case of who can hit the most winners compared to unforced errors - and believe me that there will be plenty of both. These two have played each other six times in the last two years so they will know each others games inside out. Berdych is probably a little too short for my liking but he is that price for a reason. If he fires he will win this but there is always the nagging doubt he will have one of his off days.
Selection: Berdych
Roger Federer (1) v Mardy Fish (23)
20:30 Arthur Ashe Stadium
H-to-H 8-1
Fish is no mug and Federer will need to be ready for a raucous atmosphere. The great man has an 8-1 head to head over Fish and he beat him just a couple of weeks ago. This is not an unusual stat for Federer and he definitely won't underestimate Fish. This will be a win for the number one seed but he might need a tie-break or two.
Selection: Federer
Marin Cilic (12) v Martin Klizan
22:30 Louis Armstrong Stadium
H-to-H 0-0
We have another cracking contest in store here. Cilic is gradually working into some form here with a pretty impressive win over Nishikori in the last round being his best effort so far. Klizan, on the other hand, is on fire. He is playing some of the best stuff of his career and it is no fluke as this guy has some serious game. In situations like this it is best to stick with the guy in form.
Selection: Klizan
Andy Murray (3) v Milos Raonic (15)
02:00 Arthur Ashe Stadium
H-to-H 0-1
This is a really fascinating encounter that has many possible permutations as to how the game will evolve. If Murray plays like he did against Lopez then he can start looking for flights back from JFK. However, we have all seen this from Murray before where he looks forlorn one day and then next time up he blows his opponent off the court. Raonic is a really brilliant prospect and has already beaten Murray this year so will not fear him.
Selection: Murray
Women's
Tsvetana Pironkova v Ana Ivanovic (12)
16:00 Arthur Ashe Stadium
H-to-H 1-0
It is really good to see Pironkova finally having some belief in herself and it is showing in her results. I can see a top 16 slot for her if she keeps going and maybe a scalp like Ivanovic will be just the extra boost she needs. Ivanovic is in decent form but she is not one to back at a short price. Stick with the Bulgarian and she may just reward you.
Selection: Pironkova
Andrea Hlavackova v Serena Williams (4)
18:00 Arthur Ashe Stadium
H-to-H 0-3
Against virtually anyone else I would be excited about the prospects of Hlavackova. She has been in really excellent form for the last few months and that includes two pretty hard fought defeats against Serena. Beating Maria Kirilenko in the last round was an impressive display and she knows she can compete with Serena. Unfortunately for the Czech girl she is up against the best player in her best form so there really is only one end result.
Selection: Williams
Angelique Kerber (6) v Sara Errani (10)
18:30 Louis Armstrong Stadium
H-to-H 1-1
This is a quality match-up between two top ten players. The difference here is almost certainly the surface. If it was on clay you would have to favour Errani but back on this hard court the advantage goes to the big hitting Kerber. It is clear to see that on hard courts that all of Errani's recent defeats are against the big hitters on tour as she just can't live with them on this surface. I can see a pretty easy win here for Kerber.
Selection: Kerber
Roberta Vinci (20) v Agnieszka Radwanska (2)
20:30 Louis Armstrong Stadium
H-to-H 0-4
I am not convinced that Radwanska is in her best form or shape for that matter. She hasn't been totally convincing here yet but this match-up is right in her wheelhouse. Vinci is essentially a poorer version of Radwanska and in these type of matches the number two seed very rarely loses.
Selection: Radwanska