"I don't know." Meanwhile, the rivalry lives on. "I keep letting people down", he said afterward.
Five-time Grand Slam champion Sharapova closed her remarks to a supportive crowd by saying that behind her fancy dress and sparkly crystals, "This girl has a lot of grit and she's not going anywhere".
Svitolina breezed through the first set before posting a 6-0, 6-7 (5), 6-3 victory over Siniakova, the world's 42nd-ranked player. The difference in the match was the victor count: Stephens had 43, almost double Cibulkova's 22. Apart from saluting at Flushing Meadows in 2014, the 28-year-old also reached the final at Wimbledon earlier this year, losing to Roger Federer in straight sets.
But the questions over the ban, imposed when she tested positive for meldonium at the Australian Open past year, still keep coming. Her 2006 U.S. Open title is now 11 years old, and Serena Williams is home readying to give birth to her first child.
Fifth seed Wozniacki of Denmark became the fourth top-10 woman to exit from the US Open after just two rounds when she lost 2-6, 7-6 (5), 1-6 against Russia's Ekaterina Makarova in the second round.
Sharapova, 30, clenched her left fist, slapped her thigh and shouted, "Come on, Maria!" as she rallied out of a first-set hole to down Hungary's Timea Babos, 6-7 (3), 6-4, 6-1, inside Arthur Ashe Stadium. So in a matter of 72 hours, Sharapova the underdog is suddenly an unexpected favorite, and one with an easy road to the semifinals.
Babos defeated Viktorija Golubic of Switzerland in a marathon 7-5 5-7 7-5 first round match of her own behind her commanding serve and potent groundstrokes.
The wild-card entrant from Russian Federation got past Hungarian Timea Babos 6-7 (4), 6-4, 6-1 in a second-round match that lasted two hours, 19 minutes. She holds a career Grand Slam on her resume and more than $36 million in her bank account. Kenin is an 18-year-old American with very little experience under her belt on this stage, but we know the NY crowd will be behind her as much as they can.
Sharapova was also quizzed on her fitness after two slogs with Simona Halep and Babos on the back of an injury-hit year, amid suspicions she could go all the way in NY.
She is branded and nothing Maria Sharapova does on the tennis court for the rest of her career will erase the scarlet letter "M" (for Meldonium, not Maria) that she wears on her custom-designed outfits. Sharapova finished with 12 aces and managed to overcome a whopping 19 unforced errors in the first set alone.
"I definitely wanted to enjoy the quality of tennis that I played with the other night", Sharapova said, "but I also wanted to put my mind onto this one". Babos reacted with a loud yell. She will take on fellow wild card Sofia Kenin, an American who will be an underdog as Sharapova gains strength.