Hoerner's seventh home run ended a shutout bid by Nationals starter Josiah Gray and enabled the Cubs to earn just their second win in 51 games in which they trailed entering the seventh.
"I'd seen that starter a third time," Hoerner said. "I actually don't get to do that much."
The Cubs have won four of six and next play Thursday in the Field of Dreams game in Iowa against Cincinnati.
"It's a part of history we get to do, and I'm just excited to see the whole set up on the filed," Hoerner said. "So 8,000 (fans) will feel small, but everyone will be excited to be there."
Meneses homered in his third straight game for the Nationals, who have lost seven of eight.
The 30-year-old Meneses, who made his major league debut on Aug. 2, became the first player in Nationals franchise history to homer four times in his first seven games. Danny Espinosa and Geoff Blum each hit three homers in their first seven career MLB games.
Meneses hit a solo home run in the sixth. The first baseman/outfielder also singled and is hitting .348 in the majors.
"It's what I've been looking for my whole career," Meneses said. "I've worked very hard to get to this point, and I want to enjoy every moment of it."
Gray had a 2-0 lead and had permitted five hits before Hoerner homered. Gray was puled after Yan Gomes singled.
"As we all know, (Robles) can be electric out there," Nationals manager Dave Martinez said. "But once again, it's those little things. Understanding the game, and being in a position where in a situation like that, he knows what he needs to do before it happens.
"That's the biggest thing: Think before the ball's hit to you, and understand what you need to do if the ball's hit to you."
A diving catch by Robles in the fifth helped keep the Nationals ahead.
Michael Rucker (1-1) pitched a scoreless seventh to earn his first major league win. Rowan Wick struck out Maikel Franco with the tying run at first to end the eighth and earned his sixth save in eight opportunities.
The Nationals took a 1-0 lead with two out in the third when Ortega made an unsuccessful diving attempt on a line drive by Cesar Hernandez that skipped past him in center for a double to score Tres Barrera from first.
Cubs left-hander Justin Steele was victimized by the lack of support despite striking out nine and walking none in six innings. He has allowed two earned runs while striking out 25 and walking two in his last three starts.
Steele struck out Barrera with the bases loaded to end the fourth.
"For him it's all about him being in the zone, on the attack," Cubs manager David Ross said. "He's had a nice feel for the breaking stuff. It feels like he's moving to both sides of the plate more consistently."
ROSS WANTS MORE INTERNATIONAL GAMES
Ross played in the Australian Baseball League and in Mexico City as a minor leaguer with the Dodgers, and was an announcer with ESPN for the 2019 MLB Little League Classic
Ross would like to participate in a series at Japan, where the Cubs opened the 2000 season against the Mets, as well at Puerto Rico and Cuba.
"It touches on the diversity of our game," Ross said.
STRATEGY ON SOTO
Friday's series opener against the Padres marks the return of All-Star RF Juan Soto and 1B Josh Bell to Nationals Park since they were traded for six players Aug. 2. Martinez, who managed Soto for 4 1/2 seasons, joked about his plans to pitch to Soto.
"Were'e going to walk him," Martinez said. "We'll come up with a game plan. He's got one of the best eyes I've seen for a young hitter in the major leagues."
Nationals: RHP Mason Thompson was optioned to Triple-A Rochester, presumably to make room for LHP Jake McGee, who was claimed off waivers from the Brewers.
Nationals: SS Luis Garcia (right knee soreness) was scratched from the starting lineup. ... DH Nelson Cruz (right shoulder soreness) appeared as a pinch-hitter in the eighth and singled. ... RHP Tyler Clippard (groin strain) threw two scoreless innings for Triple-A Rochester on Tuesday night and be activated as soon as Friday, Martinez said. ... RHP Erick Fedde (right shoulder inflammation) threw an extended bullpen session Tuesday and will throw a simulated game next week with the possibility he could return to the rotation. ... RHP Will Harris (thoracic outlet syndrome) suffered a groin injury during his rehab assignment and will be sidelined indefinitely, Martinez said.
The Nationals will send RHP Cory Abbott (0-1, 5.68) to the mound Friday against the Padres. Abbott allowed seven runs in 3 2/3 innings in a 13-1 loss to the Phillies Sunday.
The Cubs will start LHP Drew Smyly (4-6, 3.97) Thursday against the Reds in the Field of Dreams game at Dyersville, Iowa. Smyly pitched 6 2/3 shutout innings Saturday against the Marlins.