"He had a most unbelievable year where he won basically everything", Coric said.
Asked about her low points, Sharapova, said, "There were definitely a few but I don't think this is the time to talk about that".
Elsewhere, however, a number of players were critical of the way that tournaments lined up to offer Sharapova wild cards when her ban expired in April. "Certainly when I play against them, in terms of the level they play".
Sharapova wore a day version of her crystal-encrusted dress and, although there was less sparkle in her tennis, there was plenty of the same grit which had helped her through an epic encounter with Simona Halep in the first round. "I don't know." Meanwhile, the rivalry lives on. "I would have needed a round or two to get things started again".
Blackman says that "you don't break Roger Federer 5-3 in the fifth unless you really believe that you can win that match, and that's something you can't teach".
Maria Sharapova relied on her fighting qualities rather than top form to beat Hungary's Timea Babos at the US Open. Muguruza, last year's French Open champion, can reach the US Open third round for the first time Wednesday by defeating China's Duan Ying-Ying. But in the third, Sharapova regained control by going ahead 3-0, using her power to keep two-time French Open runner-up Halep under pressure.
Eighth seed Svetlana Kuznetsova (33/1) came much closer to exiting the tournament, saving three match points in a 4-6 6-4 7-6 (7/2) victory over Marketa Vondrousova.
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It was quickly 4-1 for Sharapova in the second set and she held a break point there to allow her to go up 5-1 and serve for the victory.
In a busy day that included 41 women's singles matches, ninth-seeded Venus Williams won her second-round match, ousting Oceane Dodin of France 7-5, 6-4.
Sharapova last participated in a major tournament at the 2016 Australian Open, where she tested positive for the newly banned heart drug meldonium.
She looked particularly nervous in the tiebreak, losing it 7-4, but ended up hitting 39 winners to 36 unforced errors.
One thing that has made the road back to the Open less tough, Sharapova said, is the encouragement from fans who backed her during her doping troubles.
Sharapova faced some hard questioning from the media when she returned to competition in Europe in the spring, but there has not been much critical comment on this side of the Atlantic over the summer. Babos reacted with a loud yell.
Sharapova did not play almost as freely as she had against Halep, when the pressure was largely on her opponent, but her famous fighting spirit was in evidence as she battled to a 6-7 (4/7) 6-4 6-1 victory.