Halep went out in the first round and Wozniacki 2nd round, leaving the former champions Maria Sharapova and Serena Williams in great positions this year. Both returned from absences and haven't yet come close to anywhere near their best. However at Flushing Meadows this year - they'll both smell blood.

Sharapova and Serena Williams could only clash in the final

Since Sharapova's book release last year, we have been reminded of the fierce rivalry between these two champions. In terms of the head-to-head - Serena Williams owns it 19-2. However, Sharapova dines out often on the 2004 Wimbledon final victory. For the US public, tennis in general and Flushing Meadows: a Serena v Maria Sharapova final would be a box office hit.

Both players still have a great deal of work in front of them to pull this off. However, they are both by far the most experienced at the pressure matches left in the field. Given that both the American and the Russian have already achieved a career Grand Slam.

Madison Keys is a potential quarter-final opponent for Sharapova

Give the regularity of the shocks this year, it'd be unwise to do too much predicting. That said, looking ahead for Maria, there is a potential last-eight clash with the uber-talented American, Madison Keys. Keys has had injury problems this year that have interrupted her US Open preparation. Although, she looked fit, focused and sharp in her 3rd round three sets victory over the dangerous Serb, Krunic.

Although it was back in 2014 - Sharapova won the only previous meeting with Keys in Cincinnati.

A victory over Keys would have Sharapova fans believing that it could be her year again.

Sharapova started slowly in the first round but seems to be motoring now

39-year-old Swiss player, Patty Schnyder clawed her way back from 5-1 down in the second set, to level the set after Sharapova cruised to the opening set in their 1st round encounter. Despite the social media furor about Sharapova choking, this could not be further from the truth. The awkward to play against the left-hander, Schnyder upper her level of play. This took Sharapova by surprise. However, she regained composure and took the set and the match in the tie-break. Sharapova never lost a set in the first three rounds.

Sharapova needs to keep unforced error countdown

Maria's best tournament this year remains her run to the semi-final of the premier level Italian Open in Rome on clay. However, this also includes her most disappointing performance. In the semi-final against Simona Halep - Sharapova had the match in her hands. Unfortunately, forty-two unforced errors and 9 double faults meant that the match slipped away. Sharapova cannot afford such concentration lapses at Flushing Meadows if she is to stand a chance of lifting the trophy for the 2nd time.