We may never know the answer to the age-old question, “Is tennis more physical or mental?” But in watching today’s match between Italy’s Karin Knapp and American Alison Riske, we can safely conclude that it’s a bit of both.

And we can declare Italy the victor of this first-round Fed Cup tie, by a lopsided 3-0 score, with Knapp’s 6-3, 7-5 victory.

The fact that Riske’s loss wasn’t just as lopsided ties back to my opening remarks. For she was a Knapp service hold away from being defeated in a similar fashion to Madison Keys, who was substituted out of singles by U.S. captain Mary Joe Fernandez.

At 5’11” and a stout 159 pounds, Knapp cuts an imposing figure, in stark contrast to her veteran compatriots Sara Errani, Roberta Vinci, and Francesca Schiavone, all of whom passed on this opening-round tie. But with her three-set win over Christina McHale and a dominant first set today, Knapp showed that the depending champions were still in capable hands.

Rather than building points like many of her countrywomen, Knapp looks for any opportunity—from as obvious as a weak second serve to as daring as an opening down the line—and takes her best shot. Riske saw plenty of those today, in part due to Knapp’s strong form but also because of her own passive play. The Pittsburgh native left too many balls short, failed to move Knapp around the court, and started many points on the defensive with weak serves.

Taking big cuts, Knapp unleashed a fusillade of forehands and did well enough with her backhand, in part because Riske didn’t target it enough. In both sets, Knapp earned a double-break lead. In the first set, she gave one break back before serving it out on her second chance.

In the second set, leading 5-2, it was a bit different. Or perhaps a bit mental.

Knapp had three chances to secure the tie for Italy, and like the first set, her insurance break came in handy. After Riske broke her clearly nervous opponent for 3-5, she held serve with ease—it was just as tight a return game for Knapp—and switched ends.

When Knapp failed to serve out the match for a second time, I wondered if I had ever seen a choke so blatantly obvious before. Looking positively frightened, Knapp failed to put a single first serve in play at 5-4, hit two double faults, and watched a backhand return winner zip by her to completely change the complexion of the match, one written off just minutes earlier.

It was not the stuff of Errani, Vinci, Schiavone, or Flavia Pennetta, all of whom have won significant titles or contributed to Italian Fed Cup glory. But as much as the pressure got to Knapp from 5-2 to 5-5, you had to admire her from that point on. She shook off losing the large lead and promptly broke Riske, who failed to adequately test Knapp from start to finish, in the very next game.

After Knapp’s mental victory came Italy’s actual victory, earned by a impressive physical display. In a throwback to her confident first set, Knapp struck two heavy forehand winners and finished off Riske, and the United States, with an unreturned serve up the T. Game, set, match, and tie to Italy, and for the second Sunday in a row, the United States lost an international competition on home soil.