Ryan, 24, and ranked 118th, is in his seventh.
Marin Cilic won 2014 US Open and then he made the semifinalist previous year. Murray later grumbled across the court to Rosol about nobody liking him. "His consistency - what I've done for, like, the last four months, he's been doing for, like, the whole year", Murray said.
Now ranked 82nd, Rosol upset Rafael Nadal at Wimbledon in 2012.
Men: No. 2 seed Andy Murray.
Murray played 14 matches in 15 days en route to winning his second straight gold medal and reaching the final at Cincinnati, when the fatigue finally caught up to him. He said Friday he's practiced lightly in NY to get used to the conditions at the U.S. Open and isn't doing any off-court work, "trying to be as fresh as I can".
Murray, Nadal, Novak Djokovic and Roger Federer have carved up 46 of the last 53 majors between them. Asked that day if he was 100 percent healthy, the 12-time major champ replied: "Not really".
When he first came back, he recalled, "you try to find movements to avoid the pain". If the German manages to overtake Serena, she will be the 22nd woman to become No 1 since computer rankings were introduced. And the words by Pliskova after the loss: "I think you (Kerber) deserve to be number one, maybe next time" must surely be a motivation to go one step further.
Serena is defending more points than any of her nearest rivals this week, having made the semi-finals of last year's US Open before suffering a shock defeat to Roberta Vinci. "You see that in the conditions like here and at the Australian Open".
While Djokovic needs to heal physically, nearly as crucial will be how well he recovers from the mental scarring of recent setbacks. He declined to elaborate on those problems other than to say they had been resolved.
It's been a harsh summer for the Serb with an early exit at Wimbledon and moreover a poor result at the Olympics in Rio where he failed to advance to the higher stages both in singles and doubles.
Doesn't always seem to matter that she owns a record-tying 22 major singles titles heading into the U.S. Open, which begins Monday with a retractable roof at Arthur Ashe Stadium for the first time. And in the fourth round, she could face Sam Stosur, who stunned her in the 2011 U.S. Open final.
Simona Halep is Williams' scheduled foe in the last eight with either fourth seed Agnieszka Radwanska or her sister Venus potentially awaiting in the semi-finals.
French Open champion Garbine Muguruza will face a qualifier in the first round, and a match with Olympic champion Monica Puig could occur in round three. He's now ranked 228th and used a protected ranking to get into the U.S. Open. Del Potro had a fairy-tale run, shocking Djokovic in round one, then beating Rafael Nadal in a classic semifinal and eventually succumbing to Murray for the silver medal. No. 6 Kei Nishikori - a finalist here two years ago - would be the projected quarterfinal opponent.
American Sloane Stephens has withdrawn from the U.S. Open because of a right foot injury.
The former world number one's comment comes ahead of Serena Williams' attempt to win her 23rd Grand Slam singles title, and break Graf's record for the most slams in the open era at the US Open. Federer had appeared in a record 65 consecutive grand slams until his absence from the French Open in May.
Stephens hadn't played since losing in the first round at the Olympics. The 17-time major champion is out of the U.S. Open for the first time since 1999, and said earlier this week it pained him to be in NY as the tournament goes on without him.
So Friday's draw could put him in position to face a seeded player in the first or second round.