The first day of a grand slam is always one to savour, with plenty of matches scattered across the fourteen courts in action on Monday. I have picked out five top matches which I think are worth keeping an eye on at Flushing Meadows.
Petra Martic (CRO) vs  Samantha Stosur (AUS) Arthur Ashe Stadium (H2H Stosur 1-0)
Last year’s winner of the Women’s title gets the honour of kicking the tournament off this year on the showpiece court here. She was a shock winner here last year defeating Serena Williams and this may put a little more pressure on the Australian’s shoulders, something that seemingly does not suit Stosur – see French Open 2010 Final and her numerous Australian Open disappointments for example. Since the clay swing has ended, Stosur has not been in great form. While her grass results are nothing new, losing to the likes of Arantxa Rus and Carla Suarez Navarro is still somewhat of a concern. However, more of a worry will be that she only made the third round in Montreal and failed to take advantage of the momentum she had after winning the second set in Cincinnati against Venus Williams. Unfortunately Martic has been out with a foot injury the past month but should be good to go here and if so she can cause Stosur problems, the Croatian was a third set tiebreak from knocking her out in Madrid this year.
 Roger Federer (SUI) vs Donald Young (USA) Arthur Ashe Stadium
The fortunes of these two players since the start of the year could not be any different. Federer surpassed Pete Sampras’ total of weeks at number one after earning his seventeenth Grand Slam at Wimbledon in July along with five other titles (Rotterdam, Dubai, Indian Wells, Madrid and Cincinnati) and a 57-8 record to boot. Meanwhile the American Donald Young has just ended his seventeen match losing streak after a comeback win against Leonardo Mayer to improve his record to 3-21 on the year. While there is no doubt that Federer wins here, it will be interesting to see the attitude that Young displays in this match. It had been clear that the losing streak was been playing on his mind and potential winning positions were not taken advantage of in previous matches. A fourth rounder here last year, Young will be hoping to keep it respectable and with Federer’s tendency not to over exert himself in early rounds he may be able to do so.
[WC] Melanie Oudin (USA) vs  Lucie Safarova (CZE) Louis Armstrong Stadium (H2H Safarova 2-0)
It has now been three years since Melanie Oudin burst onto the scene here taking out four Russians in a row – Anastasia Pavlyuchenkova, Elena Dementieva, Nadia Petrova and most notably former winner Maria Sharapova. Since then, it hasn’t gone as planned for the twenty year old who has failed to build on the results of 2009 and 2010. Late 2011 and early 2012 saw Oudin slumping and unable to win even a challenger match before she finally regained her form in Birmingham. As a qualifier, she made it all the way to the final and defeated Jelena Jankovic to earn her first WTA title. As a result of these improvements, she controversially earned a wildcard into the tournament. While Safarova should win this easily on paper, the occasion could possibly get to her head. A raucous home crowd will be well behind her opponent and she may falter as on many other occasions. Her mental frailties appeared mostly recently she failed to serve out the match twice in her Montreal semi final and eventually dropped the match to Li Na.
[WC] Jack Sock (USA) vs  Florian Mayer (GER) Grandstand
Along with Melanie Oudin, Jack Sock took the Mixed Doubles title last year but he will be hoping to make a name for himself in the singles tournament this year. Already a champion in the Boys Singles, Sock definitely has a chance to make the third round here with a softer draw than many other wildcards have. While he has not quite made the step up to ATP Tour fully yet but does have wins over Steve Johnson and Alex Bogomolov in recent weeks and really should have taken a set off the American No.1 John Isner. It is clearly from his achievements already at the tournament that the big occasion doesn’t faze him, having acquitted himself well when facing Andy Roddick on Arthur Ashe last year. Mayer, despite being a top 25 player, does not have a great record this year and has won just three times in eight attempts on hard courts this year and will have been disappointed to have lost to Marcel Granollers and Nikolay Davydenko in Toronto and Cincinnati respectively.
 Marin Cilic (CRO) vs Marinko Matosevic (AUS) Court 17
After slogging away at the lower levels of the tour for years, twenty seven year old Marinko Matosevic has finally seen his hard work rewarded with a top 100 spot. A surprise finalist in Delray Beach, Matosevic also made the semi finals in Los Angeles as well as quarter finals in Munich and Eastbourne. Meanwhile, this is the tournament that saw Cilic finally come to prominence when he defeated then No.2 Andy Murray in the fourth round. Eventually winner Juan Martin Del Potro defeated Cilic in the next round and since then he has failed to make the quarter finals stage again. Having been forced to withdraw at 3-1 in the first set at last year’s US Open, Matosevic will be hoping for much more this year and could well take a set if the Croatian lets his guard down.