Scott Hairston made the Chicago Cubs rue the day they traded him to the Washington Nationals.

Hairston, who the Nats acquired from the Cubs back in July, came on as a pinch-hitter in the seventh and stroked a tie-breaking, three-run homer to vault Washington to an 11-6 victory over Chicago on Wednesday in the third tilt of a four-game set at Wrigley Field.

"I know that he wants to show these guys what they're missing and he did a heck of a job," Washington manager Davey Johnson said of Hairston homering against his former club. "He hasn't really got big hits for us in the pinch- hit role, but that certainly makes up for anything he hadn't done in the past. That was big."

Hairston's first homer as a National made a winner out of Tanner Roark (3-0), who was charged with a pair of runs over 1 2/3 innings of relief work. Starter Ross Ohlendorf was lifted after giving up four runs on six hits in just 4 1/3 frames.

Jayson Werth stroked a three-run homer and Kurt Suzuki added two hits, two RBI and a run scored to help the Nats notch their second straight victory.

Anthony Rizzo clubbed a pair of homers among his three hits and finished with three RBI and Donnie Murphy registered an RBI and a run scored in the setback, Chicago's seventh in its last 10 games.

James Russell (1-4) was tagged with the loss after giving up Hairston's go- ahead blast in the seventh.

With the score locked at 6-6, Russell took the mound to start the seventh and retired the first two hitters he faced before Bryce Harper kept the frame alive with a double to the warning track in right-center field.

Russell then intentionally walked Werth before Hairston turned on a 1-2 changeup and crushed it into the bleachers in left to make it 9-6.

Washington tacked on two more runs in the eighth, as Suzuki smacked a one-out single and moved to second on a wild pitch with two outs.

Denard Span followed with a triple into the right-field corner to score Suzuki before crossing the plate on Ryan Zimmerman's single to right to make it 11-6.

Early on, Rizzo got the home team on the board with a line-drive shot into the seats in right-center to make it 1-0, but the Nationals responded with three runs in each of the next two innings to seize control.

A pair of one-out walks around an Adam LaRoche single loaded the bases in the second for Suzuki, who scorched a single to right to plate Ian Desmond and LaRoche for a 2-1 lead.

Ohlendorf then laid down a perfect sacrifice bunt, allowing Steve Lombardozzi to race home from third to make it 3-1.

After Zimmerman singled and Harper walked to start the third, Werth jumped on a 3-0 fastball and belted it deep into the seats in left-center to give the Nationals a 6-1 cushion.

The Cubs countered with a five-run fifth to even the score, as Rizzo launched his second homer of the night, a two-run shot to right, to bring the home team within 6-3.

Junior Lake followed with a single to end Ohlendorf's outing, as Roark entered and served up a single to Nate Schierholtz that put runners on the corners.

Murphy followed with a single to center to score Lake before Brian Bogusevic ripped a single to left to load the bases for pinch-hitter Cole Gillespie, who stroked a base hit of his own to left to score Schierholtz.

Welington Castillo then lifted a sacrifice fly to center to score Murphy and tie the game at 6-6.

"That's a tremendous job of our guys battling, getting us back in the game," Chicago starter Jake Arrieta said. "We just weren't able to hang on to it there and get the win."

Game Notes

Hairston was acquired from the Cubs on July 8 in exchange for minor-league pitcher Ivan Pineyro and a player to be named later ... Ohlendorf, who was activated from the 15-day disabled list prior to the game, recorded his first RBI since Sept. 27, 2011 for Pittsburgh ... Arrieta gave up six runs on five hits and four walks over four frames ... Chicago finished 4-for-9 with runners in scoring position and left nine men on base.