Top 5 Photos, US Open Day 2: 'Call me Coco' walks talk; Rublev rocks

Tuesday was filled with many surprises on the men's side, plus a 15-year-old prodigy met the challenge of winning her home major debut. These are the Top 5 photos that sum up Day 2 at the US Open.

1. It wasn't an easy day at the office for defending champion Naomi Osaka. The world No. 1 edged past Russian Anna Blinkova, 6-4 6-7 (5) 6-2, to capture her opener. Osaka, who was concerned about a knee injury sustained in Cincinnati, managed to hold up in a testing battle to start her title defense. In her next match, Osaka will face Magda Linette, who she defeated earlier this year during her run to the Australian Open crown.

2. Andrey Rublev posted a 6-4, 6-7(5), 7-6(7), 7-5 victory over Stefanos Tisitsipas on Louis Armstrong Stadium. Rublev fought past the No. 8 seed Tsitsipas, who suffered severe cramps midway through the fourth set but would not quit after increasing his playing tempo. After failing to serve out the match at 5-4, Rublev remained poised to advance to the second round, where he'll face Gilles Simon.

3. On a day full of action-packed play, young fans waited in excitement for the opportunity to secure autographs from top players competing on Arthur Ashe Stadium. Who knows: perhaps a future US Open champion was amongst Tuesday's crowd of aspiring champions.

4. Now firm on her first name, having declared it in a pre-tournament marketing campaign and with footwork to match, 15-year-old Coco Gauff came out tight against determined teenager Anastasia Potapova. In the midst of the second set, Gauff settled in, using the crowd support to her advantage before ultimately claiming the pressure-filled opener, 3-6, 6-2, 6-4, to win her US Open debut. Gauff will meet qualifier Timea Babos in the second round on Thursday.

5. Thomas Fabbiano upset No. 4 seed Dominic Thiem, 6-4, 3-6, 6-3, 6-2, to start his New York run. Thiem who was skeptical coming into this year's US Open due to an illness that forced him to withdraw from Cincinnati and later revealed he was "very tired and exhausted after two sets. I'm far away from 100 percent." Fabbiano will face Alexander Bublik in the second round. The Italian is aiming to move into the third round of a major for the third time this season.

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