How much can a single shot mean to a player’s season? We may find out when Madison Keys travels to New York next week and tries to win her first Grand Slam title, at the US Open.

The shot I’m thinking of came at the end of her opening-round win over Garbine Muguruza in Cincinnati. Keys was coming off a nightmarish defeat in her last event, in Toronto, where she squandered triple match point against Donna Vekic and lost in a third-set tiebreaker. On top of that, Keys was now facing an opponent, in Muguruza, who had come back to beat her in another third-set tiebreaker on these same courts in Cincinnati in 2017.

This time, though, when Keys reached match point at 5-4 in the third set against the Spaniard, she was able to put all of those memories and demons out of her mind and drill a winning backhand return. It seemed to me that a weight had been lifted from Keys’ shoulders with that shot; she hit it with a confidence that we haven’t often seen from her in recent months, and she walked off court with what looked like a renewed sense of belief and purpose.

And that’s the way she played the rest of the way in Cincinnati: Like a player who had flipped a switch on her game, and gone from doubtful to self-assured with one successful swing of the racquet. Keys beat Simona Halep, Venus Williams, Sofia Kenin and Svetlana Kuznetsova in succession, while dropping just one set. Instead of squandering leads, as she had been, Keys won the important points late in sets. Instead of oscillating wildly between winners and errors, as she often does, she measured and shaped her shots, and won rallies with two- and three-ball combinations rather than all-or-nothing blasts from behind the baseline.

“I think it was the first time in a long time that I just played a little bit more within myself, and didn’t try to do too much too soon,” Keys said after the closest of those wins, over Halep in the quarterfinals. “I think I just kind of trusted myself a little bit, and I didn’t really hold back on any of my shots.”


Madison Keys needed one shot to flip the switch and win in Cincinnati

Madison Keys needed one shot to flip the switch and win in Cincinnati

The same was true in the final on Sunday, which Keys won 7-5, 7-6 (5). In both sets against Kuznetsova, Keys fell behind an early break. But rather than let those sets go or get discouraged, she bided her time and broke to even the score at 5-5. As always, Keys won with her powerful serve and ground strokes, neither of which Kuznetsova could match; the American finished ahead in the winner count 43 to 13. But she also held her own in the long rallies, and won many of them by patiently wearing Kuznetsova down and pushing her backward, rather than trying to hit the ball through her.

This was the version of Keys that I thought we would see more of after her her title run in Charleston in April. But aside from a quarterfinal run at the French Open, she had mostly had failed to build off that result. When it came to grass and hard courts, which were once her best surfaces, Keys was struggling.

“Just one of those things where it felt like it was really close to clicking,” Keys said of her summer losses. “It just wasn’t yet.”

“Obviously the match against Garbiñe, it kind of started everything. I mean, that match was huge for me and being able to figure that out...I feel like I have played a little bit better each match since than and gotten a little more confident.”

Can she carry that momentum into the Open? If the tournament started tomorrow, I might make Keys the favorite to win it all. But even with a week off, the 2017 finalist has put herself back in the contender conversation.

“It feels a little bit better, a little less stressed,” Keys said of her expectations for the Open. “Ask me again in a week and I will be just as stressed.”

“To find that level right before a Slam obviously feels good.”

Keys is among the best players in the sport never to have won a major. Could that one shot, and one win, finally take her there?

Madison Keys needed one shot to flip the switch and win in Cincinnati

Madison Keys needed one shot to flip the switch and win in Cincinnati