WASHINGTON -- Washington first baseman Ryan Zimmerman, a University of Virginia product, faced pitcher Andrew Miller several times in college in the Atlantic Coast Conference when the lefty hurler was at the University of North Carolina.

"He has changed a lot since then," said Zimmerman, drafted out of Virginia by the Nationals 10 years ago this June. "He was a starter (and now) one of the best relievers in the game."

"I have no idea what I did against him in college," said Miller, now the closer for the New York Yankees.

But neither Zimmerman nor Miller will forget what happened Tuesday night at Nationals Park, as Zimmerman lined a two-run homer against Miller off the right-field foul pole in the last of the 10th as the Washington Nationals beat the Yankees, 8-6. The homer also scored third baseman Yunel Escobar, who had walked with one out.

"Just a bad pitch. I have to make a better pitch. It stinks," said Miller, who had not allowed a run in his first 17 outings this year. "You never want to give up a run to lose a game. It has been a good start (to his season), but it is still not a good feeling. I have to throw a better pitch there."

Said Yankees manager Joe Girardi of Miller, whose ERA went from 0.00 to 0.98: "He is not going to be perfect. I am sure he will be fine. He has given up runs before."

It was the 10th career walk-off homer for Zimmerman, the 11th comeback win of the year for the Nationals and the third walk-off victory this season for Washington.

"I'm just happy with the win. That is the most important thing," Zimmerman said. "I am lucky to be in that situation that much."

The ninth victory in 11 games for the Nationals (23-17) came on a day that outfielder Jayson Werth went on the disabled list with a left wrist contusion. "I wish it was better. I'm optimistic," Werth said after the game.

The Yankees have their own injury problems with an outfielder as center fielder Jacoby Ellsbury left the game in the fourth inning with a right knee injury. "It's not what you want. Somebody has to step up. It is part of the game," said Girardi, who added he won't know more about the condition of Ellsbury until after an MRI.

Washington catcher Wilson Ramos' solo homer on a 3-0 pitch from David Carpenter had tied the game at 6-6 in the sixth. The hit extended Ramos' hitting streak to 19 games, the longest of his career and the longest current streak in the majors.

The first-place Yankees (22-18) lost for the seventh time in 11 outings. The winner was rookie Matt Grace (2-0), who pitched a scoreless 10th, while Miller (0-1) was stuck with the loss. "The frustration is we had the 6-2 lead and they were able to come back and tie it up," Girardi said.

Washington shortstop Ian Desmond and Escobar each had two hits, as did Yankees shortstop Stephen Drew and first baseman Mark Teixeira.

Wilmer Difo, a top infield prospect in the Nationals system, made his big league debut as he pinch-hit to lead off the seventh against Carpenter. He lined a single up the middle for his first major league hit. "That is always an exciting thing," Difo said through a translator.

The Nationals took a 2-0 lead in the first on solo homers by Desmond and right fielder Bryce Harper. Desmond hit his third homer with one out to right-center and Harper, with two outs, hit a liner to nearly the same spot for his league-leading 15th homer of the season.

Washington manager Matt Williams said before the game it was "unreasonable" for Harper to keep up his torrid pace. But it was the 10th homer in the last 12 games for Harper, who increased his RBI total to 38 with the homer off New York starter Nathan Eovaldi.

The Yankees scored four in the fourth to take a 4-2 lead. Teixeira hit a two-run homer in the fifth to give the Yankees a 6-2 lead. It was the first homer in 10 career games at Nationals Park for the first baseman, who has now gone deep in 24 of the 30 current major league parks.

The Nationals scored three in the fifth as pinch-hitter Clint Robinson had an RBI double and Desmond and Escobar drove in runs with singles to make it 6-5. "We knew we were going to play baseball like we were supposed to," Zimmerman said of the team's 7-13 start to the year.

NOTES: Washington OF Bryce Harper entered the homestand on Tuesday with three homers and nine RBIs with 12 hits in his last 23 at-bats. On Monday, he was named the National League Player of the Week for the second week in a row. ... Washington OF Jayson Werth, hitting .208 with two homers in 101 at-bats, went on the 15-day disabled list Tuesday with a left wrist contusion after he was hit by a pitch on Friday in San Diego. INF Wilmer Difo was called up from Double-A Harrisburg to fill the roster spot. ... Yankees 1B Mark Teixeira was in the starting lineup after he was hit in the foot with a pitch on Sunday.