Is destiny on the side of Novak Djokovic? The world No?1 arrived in New York as a persecuted figure, haunted by rumours of private angst and physical frailty. Yet the draw has parted in front of him like the proverbial Red Sea.
After a sequence of no-contests against exhausted or injured opponents, Djokovic has only 6hr 26min of court time on the clock - barely longer than one of his five-set battles with Rafael Nadal. He has also ticked off yet another first, becoming the only player in the Open era to arrive in a grand-slam semi-final with just two completed matches under his belt.
Perhaps Djokovic has earned some of his good fortune. A half-fit player might push through a niggle against other opponents, but everyone knows that you don't beat the world No?1 without running at 100 per cent.
The latest retiree was Jo-Wilfried Tsonga on Tuesday, who did at least manage to complete two sets before admitting defeat. "I knew it was over for me straightaway," Tsonga explained afterwards, "because when I have my knee, it's already tough to play against one of the best tennis players." In the earlier rounds, Mikhail Youzhny - who managed 32 minutes in their third-round match - and the non-runner Jiri Vesely also ushered Djokovic through without fuss.
The upshot is that Djokovic's mood has performed a 180-degree turn.
Irritable and jittery at the start of this event, he is now broadcasting his familiar serenity to the tennis world. And why not?
Today he can look forward to an inviting semi-final against Gael Monfils - whom he has beaten in each of their 12 previous meetings.
"In this stage of the season, considering some physical issues I have had in the last month, month and a half, this was the scenario that I needed and I wished for," said Djokovic on Tuesday night.
"I got a lot of days off and recovered my body. Right now I'm feeling very close to the peak. That's the position where I want to be."
Might he not be a little undercooked if one of his two remaining matches turned into a marathon? "Not really. I was so many times in the situation where I had long matches on the road to the semis of a grand slam.
"It really just depends how you feel, how your season has been, how many matches you have played throughout the year."
He added: "As I said, this scenario was ideal at this stage."