CHICAGO -- Without Stephen Strasburg, Max Scherzer or Giovany Gonzalez, the Nationals turned to journeyman Edwin Jackson on Saturday afternoon at Wrigley Field. The Cubs roughed up the 33-year-old right-hander with a four-run first inning, and Willson Contreras added a two-run homer in the sixth to post a 7-4 win over the Nationals and snap a three-game losing streak.
Contreras, starting in left field rather than at catcher to keep his hot bat in the lineup, hit an RBI single in the first while Alex Avila added a two-run homer -- his first hit since joining the Cubs -- and Kristopher Bryant smacked an RBI double to back John Lackey, who improved to 4-0 in his past five starts.
"It's a challenge to face that lineup, regardless of what time of year it is," Lackey said of the Nationals.

Since the All-Star break, Contreras has hit eight home runs and driven in 27, both tops on the team. With the win, the Cubs maintained a half-game lead in the National League Central over the Brewers, who also won Saturday. Chicago now is 15-6 since the All-Star break.
Told that Cubs manager Joe Maddon wanted to make sure he was in the lineup, Contreras smiled.
"That tells me they have a lot of confidence [in me]," Contreras said. "Thank God I'm able to keep hitting well and keep having important RBIs in the game."

Lackey did give up Bryce Harper's 28th home run in the first inning, which bounced off the video board in right field. Harper also threw out a runner at third with a perfect strike in the bottom of that frame, and he robbed Jonathan Jay of a potential extra-base hit with a running catch in the fifth. The Nationals had a chance with two outs in the ninth, with Harper at the plate before the Cubs' Wade Davis struck him out to seal the victory.
"He's one of the best closers in the game," Harper said of Davis. "Definitely tough in that situation. I got one pitch I can drive and hit it foul. I knew if I missed a pitch against him, it would be a tough at-bat."

And if Davis had missed at any point in the at-bat, the game could've been tied.
"The last curveball [from Davis to Harper] was an unbelievable pitch and pretty nasty," Avila said. "It looked like a fastball out of his hand, and it just kind of fell off the table and perfect location, down and away, looking for that swing and miss. You couldn't have asked for a better pitch."
The Nationals have a 13-game lead in the NL East over the Marlins, who lost to Atlanta on Saturday. Strasburg and Scherzer were sidelined with injuries while Gonzalez was on paternity leave. This was Jackson's fourth start with the Nationals, and he struck out eight over five innings, scattering six hits. He settled in after giving up four runs in the first inning to not allow a run during his final four innings.
"From then on, it's just keep the game close," Jackson said. "... We can definitely come back from three runs, and that was my objective."

MOMENTS THAT MATTERED
Jump start: Jay and Bryant hit back-to-back doubles to open the Cubs' first and tie the game at 1. One out later, Bryant scored on Contreras' swinging bunt. Contreras was erased trying to advance on Benjamin Zobrist's single, but Avila followed with his first hit with the Cubs, a home run 412 feet to straightaway center, to open a 4-1 lead.
"I'm glad to get that first one out of the way," Avila said.
Ricochet: In the Nationals' fourth, Ryan Zimmerman singled and reached third on Daniel Murphy's single. Zimmerman then scored on Anthony Rendon's sacrifice fly to left. Contreras, making his third start in left field, did throw home, but the ball bounced off Zimmerman. One out later, Matt Wieters hit an RBI single to close the gap to 4-3.

QUOTABLE
"Today was like an American League game, to be honest. That lineup is more of an American League lineup -- at least that's what it felt like to me, trying to navigate through that order." -- Avila, on facing the Nationals
"They're great. They're some of the best fans in baseball. It's a lot of fun being out there and interacting with them. They're classy. They go out there and do their thing. They say some things that are funny. I enjoy going out there and going back and forth with them. Like I said, they're classy fans. They do it the right way. It's a lot of fun to go out there and hang out with them." -- Harper, on Cubs fans
SOUND SMART WITH YOUR FRIENDS
Davis has converted 23 consecutive saves, a single-season club record. It's the second-longest streak in Cubs history, trailing Ryan Dempster's 26-save streak in the 2005-06 seasons.
GLOVE WORK
Harper put the Nationals on the board first with his 28th home run, then made the defensive play of the game in the Cubs' half when he threw out Contreras trying to advance to third on Zobrist's single. According to Statcast™, Harper's 185-foot throw from right was clocked at 97.8 mph.

"I was just trying to be aware of what people are going to do," Harper said. "Contreras is a catcher. He can run a little bit. You never know. I was ready to go."
WIETERS EJECTED
Wieters was ejected after the sixth inning for arguing balls and strikes with home-plate umpire Chad Whitson. After Jason Heyward struck out swinging to end the inning, Wieters stopped before heading to the dugout to voice his displeasure with Whitson and was thrown out of the game in between innings.

"I was more arguing that they had a different strike zone than we had," Wieters said. "That's what I thought for most of the game. Our left-handed hitters were getting some pitches called that were off the plate to them, and we had a couple pitches that last inning that we didn't get that were really close, if not strikes. His opinion obviously differed from mine, but I thought they had a little bit more liberal strike zone, for whatever reason, on the outside corner today."
WHAT'S NEXT
Nationals:Erick Fedde, the Nats' top pitching prospect and No. 3 prospect on the team according to MLBPipeline.com, will take the mound for Sunday's series finale at Wrigley Field. It will be Fedde's second career start after he gave up seven runs on 10 hits in four innings against the Rockies in his MLB debut last week. First pitch is at 2:20 p.m. ET.
Cubs:Jonathan Lester will close the homestand and the series on Sunday. In his last start against the D-backs, he gave up three runs on five hits over four innings, and he had to be lifted early because of a high pitch count. Lester also hit his first Major League home run in that game. He faced the Nationals in Washington on June 29, giving up one run over six innings, but he did not get a decision. First pitch is scheduled for 1:20 p.m. CT.
Watch every out-of-market regular-season game live on MLB.TV.