The disparity between the Pittsburgh Pirates and visiting New York Yankees is easy to spot -- in record, statistical comparisons, payroll -- but that's not the whole story.

Or at least it isn't through the first half of a two-game series between the clubs that concludes on Wednesday in Pittsburgh. The Pirates put together a strong game in all aspects to take the series opener 5-2 on Tuesday.

While a sweep of a two-game series might seem underwhelming, it would carry some significance for a Pirates team that is 14 games under .500 and at least partially rebuilding. The Yankees are the top team in baseball.

"This team fights," said Pittsburgh outfielder Jack Suwinski, who hit his 14th homer Tuesday to lead all National League rookies.

"We're a really good team. I believe that. Everyone in the clubhouse believes that. We all believe that we can play the best teams, no matter who it is, and put together good games."

In late May, the Pirates went to Los Angeles when the Dodgers had baseball's best record and swept a three-game series. Pittsburgh manager Derek Shelton said games like those and Tuesday's can be strong teaching moments for young players.

"I think it shows them that if you pay attention to the little things ... little things are important," Shelton said.

The Yankees could use a few more little things -- and big things, namely runs -- in the series finale on Wednesday.

New York was coming off a 2-0 road loss Sunday against the Cleveland Guardians, so the Yankees' powerhouse lineup has managed just two runs during a two-game losing streak.

One of the Yankees' better hitters, first baseman Anthony Rizzo, was a late lineup scratch on Tuesday because of lower back stiffness. It sounds as if he could miss the series finale, too.

"He just couldn't get loose," New York manager Aaron Boone said. "Might be a couple of days."

The Pirates will try to hand the Yankees just their second three-game skid on Wednesday. New York right-hander Luis Severino (4-3, 3.35 ERA) is scheduled to oppose Pittsburgh right-hander Mitch Keller (2-5, 5.14).

Severino is coming off a hard-luck loss against the Houston Astros on Thursday, when he gave up two runs and three hits in six innings. He struck out four and walked two.

"I think he has been really good," Boone said. "I feel he has been really consistent for us, and his stuff has been excellent. To me, he looks like the pitcher -- and maybe even a more polished version of the pitcher -- that has been wildly successful in this league and in his young career.

"I feel like we got Sevy back, and that's been the most encouraging thing."

Severino made the American League All-Star team in 2017 and '18 and finished third and ninth in AL Cy Young voting in those years, respectively.

He has never faced Pittsburgh.

Keller, who likewise has never faced the Yankees, had a rough outing in his latest start during what could be a make-or-break season.

Keller did not get a decision against the Washington Nationals on June 29, when he gave up five runs, four earned, and nine hits in four-plus innings with four strikeouts and four walks. That marked the only time in six starts since he returned to the rotation at the end of May that he allowed more than three runs.