Rafael Nadal vs. Diego Schwartzman: Score and Reaction from 2015 US Open

The 2015 U.S. Open continues to be anything but a cakewalk for Rafael Nadal, as he labored in the second round against Diego Schwartzman on Wednesday evening. The two-time U.S. Open champion won in straight sets, 7-6(5), 6-3, 7-5, but the result nearly could've gone the other way given how poor Nadal looked for stretches.

In his first match of the tournament, Nadal received a major test from Borna Coric. Coric was largely a non-factor in the first two sets but won the third and pushed Nadal hard in the fourth before the Spaniard prevailed.

Speaking in his post-match interview, Nadal chalked up his struggles in part to the conditions in Flushing Meadows on Monday night.    

"I started playing well, first set was a very high level," the 14-time major champion said, per ESPN.com's Greg Garber. "The conditions tonight [were] very humid. For me, I am sweating a lot. When [we have] those conditions, I suffer a little bit more."

That feeling of fatigue may have carried over into Wednesday's match.

Things looked to be progressing well for the eighth seed after he jumped out to an early 3-0 lead. Perhaps Schwartzman was having trouble dealing with the jarring visual of Nadal's selection of clothing for the match, per tennis commentator David Law:

After going down 2-5 in the set, Schwartzman rebounded to win the next three games and tie the match at 5-5. He then held serve in the 12th game to send the set to a tiebreaker.

Despite continuing to look far below his best, Nadal managed to secure the first set 7-5 in the tiebreak. You can see how much set point meant to him after he put Schwartzman away with a heavy forehand, per U.S. Open Tennis:

Nadal seemed to be pressing a bit, trying to win a point with a fantastic shot when a more conservative route would've been the way to go. That was evident by his 17 unforced errors in the first set—three more than Schwartzman had.

Jessica Luther posited that things could quickly turn more positive for Nadal over the remainder of the match:

"

Nadal looks shaky. But so did Serena and now she's one game from her second-round win.

— Jessica Luther (@scATX) September 2, 2015"

Luther's statement proved true in the second set.

Nadal continued to look off his game in the early stages, and Schwartzman went ahead 2-0. Then, Nadal slowly started asserting himself. His groundstrokes were crisper, and he was serving much better. His first-service percentage rose from 62 percent in the first set to 79 percent in the second.

Nadal's unforced errors also fell to seven, while his success in medium rallies improved from 50 percent to 58 percent.

Schwartzman remained dogged in his pursuit of a win despite going two sets down. History, however, was firmly against him, per ESPN Stats & Info:

Nadal again reverted to his first-set self, picking up 16 unforced errors. He looks almost rusty despite his pre-tournament preparations and below his physical peak. Shots Nadal would normally reach with ease because of his prodigious athleticism and stamina were more difficult for him Wednesday.

As a result, he was either forced to take more chances to end points more quickly or unable to fully measure up the shot and didn't get a great swing on it. Both cases led to Nadal's inflated unforced-error totals.

But as much as Nadal labored, Schwartzman was unable to extend the match, in large part because of his serving in the third set. The 23-year-old won just 15 of his 28 first-service points, a percentage that will always cause trouble against great opponents like Nadal.

Nadal did just enough to take the set and the match.

He draws Fabio Fognini in the third round, which should be a fun, competitive match. Although Nadal is 5-2 over his career against Fognini, the Italian has won two of their three meetings in 2015. Brad Gilbert believes Nadal could have his hands full:

Based on his first two matches, Nadal is vulnerable. If Fognini can take the first set or push it to a tiebreak, he may be able to pull off the upset. Nadal has played quite a bit of high-pressure tennis over the last three days, and that could soon catch up with him.

Note: All stats are courtesy of USOpen.org.