SAN DIEGO -- Washington manager Dusty Baker saw it as good hitting. Padres pitcher Erik Johnson called them mistakes.

Bryce Harper, Wilson Ramos and Anthony Rendon all clubbed homers on two-strike pitches Thursday night to lead the National League-East leading Washington Nationals to an 8-5 win over the struggling Padres at Petco Park.

Harper and Ramos hit back-to-back, opposite-field shots off Johnson in a three-run third that overcame an early Padres' and carried the Nationals to a second straight and ninth in 11 games. The loss was the Padres fifth in their last six games.

"It was nice to see Bryce take that pitch to the opposite field," Washington manager Dusty Baker said of the two-run homer that put the Nationals ahead to stay at 3-2.

Jayson Werth started the Nationals' decisive rally with a two-run single. The left-handed-hitting Harper then drove a two-strike fastball 359 feet into the corner seats in left. The right-handed-hitting Ramos followed with a 393-foot drive into the right-field seats ... again with two strikes.

Rendon hit the third homer off Johnson on a 0-and-2 pitch in the sixth.

"If you give up seven hits and three leave the yard, it's not good said Johnson, who has given up five home runs over 10 2/3 innings in his first two starts since joining the Padres in the June 4 trade that sent right-hander James Shields to the Chicago White Sox.

"All three homers were on pitches with two strikes that were away."

"I think tonight was a step forward," Padres manager Andy Green said of Johnson, whose earned run average as a Padre is 8.44. "But he was living predominantly on one side of the plate. And he was stung by the long ball."

The Nationals never trailed after Harper's 14th home run of the season.

"I'm looking for balls that I can crush," said Harper, who apparently got one from Johnson. "I like swinging at pitches that are away."

Ramos followed Harper with his 11th homer of the season giving the Nationals their ninth set of back-to-back homers this season.

Right-hander Tanner Roark allowed four runs on seven hits and two walks with five strikeouts over six innings to get the win and improve to 6-4. Shawn Kelley, who was with the Padres last season, came on in the ninth to get his second save.

"Kelley showed me he wants the ball," said Baker, who has lost closer Jonathan Papelbon to the disabled list. "Tanner was good. He's a fighter. He was always battling."

"I wasn't aggressive enough," said Roark, who spotted the Padres a 2-0 lead in the first. "Early on, I was falling behind and not making the pitches I needed to."

Travis Jankowski singled to center to open the Padres' first and moved to second on a walk to Wil Myers. Matt Kemp singled to center to score Jankowski. Myers scored on a one-out single by Melvin Upton Jr.

The Nationals got one run back in the top of the second after Ramos and Clint Robinson opened the inning with back-to-back singles. Ramos reached third on a force out and scored on a sacrifice fly to center by Stephen Drew.

Then Harper and Ramos struck to make it 4-2 in the third. The Padres pulled to within a run in both the fifth and the sixth. But the Nationals responded each time with a run in the top of the following inning.

Myers hit his 14th homer with one out in the fifth. The 357-foot drive to left was the eighth homer run in the past 15 games for the first baseman who said he'd participate in Home Run Derby at Petco Park on the eve of the All-Star Game if invited. But Rendon answered with his solo shot in the top of the sixth.

In the bottom of the sixth, Upton singled, stole second as Ryan Scimpf struck out, stole third and scored on Christian Bethancourt's ground out to short to make it 5-4. Again, the Nationals countered in the top of the next inning. An error by Padres second baseman Yangervis Solarte and two walks -- one intentional -- issued by left-handed reliever Brad Hand loaded the bases with one out. Ben Revere scored on a sacrifice fly to left-center off the bat of Robinson.

NOTES: The Padres rested three regulars Thursday night in the opener of the four-game series. SS Alexei Ramirez had started 33 straight games, CF Jon Jay had made 26 straight starts and C Derek Norris also sat. ... RHP Tyson Ross, who has been on the disabled list since the day after opening day, played catch from 150 feet and threw from in front of the mound Thursday, and is expected to throw from the mound within the next week.