CHICAGO -- Cubs manager Joe Maddon wanted to start Alex Avila, but he also wanted to keep fellow catcher Willson Contreras' bat in the lineup. So Maddon put Contreras in left field.

Having both catchers in the lineup paid off Saturday.

Avila and Contreras each homered to help the Cubs beat the Washington Nationals 7-4 and even the division leaders' three-game series at one victory apiece.

Avila, who joined the Cubs in a trade with Detroit on Monday, is impressed by his new, younger teammate.

"It doesn't seem like he gets tired. It's nice being that age," Avila said.

Avila and Contreras combined to drive in five runs as the Cubs snapped their three-game losing streak.

"He's swinging the bat so well and how about Alex?" Maddon said. "Alex did a nice job. That home run really got us rolling. I like Alex behind the plate too. He's a very calm presence. He followed the game plan really well. He's just been on board a couple days, but he's very bright and he follows it well."

Bryce Harper hit his 28th home run for National League East-leading Washington, which has lost three of its last four.

Harper homered off the right-field videoboard to give the Nationals the lead in the first inning. Cubs starter John Lackey has allowed 27 home runs, tied for the most in the majors.

The Cubs, who were holding a slim lead over the Milwaukee Brewers in the NL Central, came back with a four-run bottom of the first. Jon Jay and Kris Bryant hit back-to-back doubles to tie the game before Contreras' infield single put the Cubs ahead.

"We need to keep putting him out there," Maddon said about Contreras, though he noted Contreras will likely get a day off Sunday.

Avila then smacked a two-run home run for his first hit as a Cub since Chicago acquired him.

"Every game matters from now 'til the end of the season," Avila said. "It's been a couple years since I've been playing meaningful baseball at this point in the season. It feels good. I'm excited to be a part of it."

The Nationals pulled within one with two runs in the fourth. After two singles, Anthony Rendon's sacrifice fly and left fielder Contreras' throwing error brought in a run, and Matt Wieters' two-out single drove in another.

Contreras' two-run home run, his 19th of the season, gave the Cubs insurance runs in the sixth inning. He homered off reliever Matt Grace after Anthony Rizzo singled.

"He has tremendous ability, has an idea how to use it," Avila said. "I told him a few days ago when I got here, 'I'm here not only to help the team win but to help you.' I'm going to keep myself available for him. As he gets older, he's going to notice some things about himself and the league and his baseball IQ will only go up from here."

Jay added an RBI single in the seventh for the Cubs.

The Nationals scored a run on shortstop Javier Baez's error on a double-play attempt in the eighth.

Lackey (9-9) allowed three runs (two earned) in five innings. He was 3-0 with a 3.27 ERA in July.

Wade Davis earned his 23rd save despite walking two in the ninth. With two on, he struck out Harper to end the game.

"I just always believe we have a chance to come back, especially when we have the tying run at the plate and Bryce and the winning run on deck with (Ryan Zimmerman)," Nationals manager Dusty Baker said. "We were just hoping to get down to (Daniel) Murphy and Rendon. (Davis) was having a rough time finding the plate and we just came up short."

Nationals starter Edwin Jackson (2-2) struck out eight and walked none but gave up four runs in five innings against his former team. He pitched for the Cubs from 2013-15. Previously, he was 3-5 with a 5.89 ERA in 10 career appearances against Chicago.

"I couldn't get the ball down in the first inning. I had a couple balls hit that were up in the zone," Jackson said.

Jackson started in place of left-hander Gio Gonzalez (9-5, 2.66 ERA), who went on the paternity list.

"Jackson threw the ball pretty well except for the home (run)," Baker said.

NOTES: The Nationals recalled RHP Erick Fedde from Triple-A Syracuse and placed LHP Gio Gonzalez on the paternity list Saturday. ... RHP Stephen Strasburg (right elbow nerve impingement) is making progress in his throwing program, the Nationals announced Saturday. He has been on the disabled list since July 27. ... Cubs C Willson Contreras made his third start in left field this season Saturday against the Nationals. Contreras replaced Kyle Schwarber, who is batting .192, in left field. Manager Joe Maddon said he wanted to keep Contreras' bat in the lineup. Contreras was hitting .429 during the homestand entering Saturday. ... Cubs C Alex Avila caught RHP John Lackey for the first time since they acquired Avila from the Detroit Tigers on Monday. ... Nationals C Matt Wieters was ejected between the sixth and seventh innings for "talking" to home plate umpire Chad Witson, manager Dusty Baker said. "It was a very, very quick hook in my opinion and took us down to one catcher," Baker said.