There were four Australians in action on the opening day of the final Grand Slam event of 2013 and two of them made it through to the second round and two didn’t.
Three of those were men and 20-year-old world No. 52 Tomic came back from two sets to one down to beat Spain's Albert Ramos in five sets, but other two Australian men didn’t manage to advance.
Marinko Matosevic pushed Spanish veteran and 19th-seed Tommy Robredo to four sets but fell short in the end while 18-year-old Nick Kyrgios made his US Open debut with a competitive loss to world No. 4 David Ferrer.
Tomic was frustrated coming into the tournament with his father John not granted accreditation as he returned to the scene of last year's tanking allegations.
It might have been easy for him to throw in the towel after losing the second and third sets against the world No. 75 Ramos as well, but he showed terrific fight to claim the last two sets and win the match, 6-3, 3-6, 4-6, 7-6 (1), 6-3.
Tomic will now face British youngster Daniel Evans in the second round.
Matosevic's horror first round run at Grand Slam tournaments continued as well with the 31-year-old Robredo beating him 6-3, 6-7 (6), 6-3, 6-2 meaning Matosevic has now lost 11 straight Grand Slam first round matches.
Meanwhile, Kyrgios was always facing an uphill battle in his US Open main draw debut up against world No. 4 and French Open finalist Ferrer, and the Spaniard proved too good winning 7-5, 6-3, 6-2 but the Australian teenager did well to put up a solid fight.
The only Australian female in action was 19-year-old emerging star Barty and she put in a terrific effort to beat Spaniard Estrella Cabeza Candela 6-1, 6-4 as she advanced to a Grand Slam second round for just the second time.
Barty will now next face Russian No. 32 seed Anastasia Pavlyuchenkova in the second round.
In other men's action on Day 1, Rafael Nadal, Richard Gasquet, Janko Tipsarevic, Feliciano Lopez, Nikolay Davydenko and Dmitry Tursunov were among those to advance.
Japan's No. 11 seed Nishikori and Spanish veteran Fernando Verdasco, however, were the biggest casualties of the opening day.
Nadal can return to the world No.1 ranking if victorious at Flushing Meadows and he had little trouble in the opening round beating American Ryan Harrison 6-4, 6-2, 6-2.
The Spaniard will next face the winner of the Rogerio Dutra Silva and Vasek Pospisil clash.
Frenchman Gasquet scored a comfortable 6-3, 6-4, 6-2 win over another American Michael Russell to set up a second round encounter with his Stephane Robert after he beat another French player Albano Olivetti 6-3, 6-3, 6-4.
Croatia's Ivan Dodig scored an upset when he prevailed in five sets over 27th-seed Spaniard Verdasco 6-3, 7-5, 1-6, 4-6, 6-3.
Hot-headed Serb Tipsarevic is through to the second round where he will play Israeli Dudi Sela after beating Uruguay's Pablo Cuevas 6-3, 6-7 (5), 6-3 with Cuevas retiring hurt. Sela beat Russian Andrey Kuznetsov in five sets, 7-6 (2), 6-3, 6-7 (2), 5-7, 6-4.
The biggest upset of the day came when British youngster Evans upset Japan's Nishikori 6-4, 6-4, 6-2.
American Bradley Klahn beat Frenchman Kenny de Schepper 6-7 (5), 6-2, 7-6 (0), 7-6 (4) to book in a second round battle with Spanish No.23 seed Lopez who beat Frenchman Florent Serra 6-7 (4), 6-2, 6-3, 6-3.
Russian veteran Davydenko also had a five-set battle with American Rhyne Williams, but he ended up winning 6-3, 4-6, 1-6, 7-5, 6-0 and will now face Dodig in the second round.
There was yet another five-set battle between Austrian Andreas Haider-Maurer and Latvian Ernests Gulbis, with Haier-Maurer winning 3-6, 6-3, 1-6, 7-6 (4), 6-4 to book in a second round match-up with Mikhail Kukushkin who beat Andrej Martin 6-4, 7-6 (2), 7-5.
Roberto Bautista Agut comfortably beat Brazilian Thomaz Bellucci 6-3, 6-2, 6-2 to book a second round match-up with Ferrer.
Russian Dmitry Tursunov beat Slovak Alijaz Bedene 7-5, 4-6, 6-3, 6-0 and the No. 32 seed will now face Guillaume Rufin in the second round after the Frenchman beat German Jan-Lennard Struff 7-6 (4), 6-3, 2-6, 2-6, 6-1.
Canadian Frank Dancevic beat Dutchman Robin Haase in four tight sets 7-6 (5), 3-6, 7-5, 7-6 (3) and he will now take on Spaniard Robredo in the second round.
He will next face the winner of the Philipp Kohlschreiber-Collin Altamirano clash.
Meanwhile, Agnieszka Radwanska, Venus Williams, Serena Williams, Li Na, Sloane Stephens, Jelena Jankovic, Laura Robson, Jamie Hampton, Sabine Lisicki, Angelique Kerber, Sorana Cirstea, Bethanie Mattek-Sands and Yaroslava Shvedova won their women's singles opening round battles.
Kirsten Flipkens, Francesca Schiavone, Madison Keys, Kimiko Date-Krumm, Anabel Medina Garrigues, Marina Erakovic didn’t though.
World No. 3 Pole Radwanska had no trouble advancing to the second round with a dominant 6-1, 6-2 win over Spaniard Silvia Soler-Espinosa.
Radwanska will now next face another Spaniard, Maria-Teresa Torro-Flor after she beat New Zealand's Erakovic 6-0, 6-4 in the first round on Monday.
Venus Williams scored the biggest opening day women's upset when the 33-year-old seven-time Grand Slam champion knocked off No. 12 seed Belgian Flipkens. The American veteran prevailed in a dominant showing, 6-1, 6-2.
Williams will now take on China's Jie Zheng in the second round after she beat Dutchwoman Kiki Bertens 6-1, 6-3 on Day 1.
Venus' younger sister Serena is shooting for her 17th career Grand Slam and second of 2013 and she got off to a blistering start against another former major winner, Italian veteran Schiavone, record an emphatic 6-0, 6-1 victory.
Serena now takes on Kazakhstan's Galina Voskoboeva in the second after she downed Romania's Monica Niculescu 6-4, 6-3.
Another former major winner, China's Li Na, is also through to the second round after beating Belarusian Olga Govortsova 6-2, 6-2 on Monday.
The No. 5 seed will now face Swede Sofia Arvidsson who beat Czech Petra Cetkovska 1-6, 6-4, 6-1.
American excitement machine Stephens had a score against Luxembourg's Mandy Minella but ended up winning 4-6, 6-3, 7-6 (5) in a thrilling battle.
The 15th-seed will now next face Poland's Urszula Radwanska who prevailed comfortably over Romania's Irina-Camelia Begu 6-1, 6-3.
American youngster Keys proved no match for former world No. 1 and ninth-seed Jankovic with the Serb prevailing 6-3, 6-4. She will now face Russian Alisa Kleybanova who beat Monica Puig 6-4, 3-6, 7-5.
British youngster Robson is the 30th-seed coming into the US Open and she is now into the second round after a 7-5, 6-0 win over Spain's Lourdes Dominguez Lino. She now takes on Frenchwoman Caroline Garcia who downed American Shelby Rogers 6-3, 6-2.
Another American Hampton won through to the second round with a 6-4, 6-2 win over Spain's Lara Arruabarrena. She will face Frenchwoman Kristina Mladenovic who won a three-set battle over Spanish veteran Anabel Medina Garrigues 6-1, 1-6, 6-1.
Wimbledon finalist Lisicki had little trouble winning through to the second round beating Russian Vera Dushevina to set up a second round clash with Argentina's Paula Ormaechea who beat Japanese veteran Date-Krumm 6-3, 7-6 (7).
Canada's Eugenie Bouchard beat Czech Karolina Pliskova 4-6, 6-4, 7-5 to set up a second round clash with eighth-seeded German Angelique Kerber who downed Czech Lucie Hradecka 6-1, 6-1.
Carla Suarez Navarro scored the most emphatic win of the opening day thrashing American Lauren Davis 6-0, 6-0 to book a second round clash with American Coco Vendeweghe who downed Serbia's Aleksandra Krunic 6-4, 7-6 (5).
Estonia's 25th-seed Kaia Kanepi won through to the second round with a 4-6, 7-6 (4), 6-1 win over American Vania King and she will next face Slovak Anna Schmiedlova who beat Swiss Stefanie Voegele 6-1, 5-7, 7-6 (4).
Romania's 19th-seed Cirstea beat Canada's Sharon Fichman 7-5, 5-7, 6-1 to book a second round encounter with Japan's Karumi Nara who downed Romania's Alexandra Cadantu 6-2. 6-2.
Colourful American Mattek-Sands also won through beating Frenchwoman Mathilde Johansson 6-3, 6-1 to book in a second round clash with Russian Ekaterina Makarova who beat Slovak Polona Hercog 6-2, 6-4.