CHICAGO -- Jake Arrieta didn't get the win, but the Cubs did, as Javier Baez smacked a walk-off home run with one out in the 13th inning to beat the Nationals, 4-3, on Sunday and complete a sweep in front of 41,233 at pink-splashed Wrigley Field for Mother's Day. It was the seventh straight victory for Chicago, which became the 10th team to win at least 24 of its first 30 games and the first since the 1984 Tigers (26-4).
"It was a team win," Arrieta said. "We grinded it out."
Kris Bryant had tied the game at 3 with a two-run single in the seventh. In the 11th, Jason Heyward tried to score from first on Bryant's one-out double, but he was thrown out at home on a perfect 8-6-2 relay. With one out in the 13th, Baez launched a 2-2 pitch from Blake Treinen into the left-field bleachers. It was the Cubs' first walk-off win of the season, and the first walk-off homer since Chris Denorfia did so last Sept. 28 against the Royals.
"You can see how much power he's got," Cubs manager Joe Maddon said of Baez. "That had rockets on it, man, and that was really well struck."
Bryce Harper tied a Major League record with six walks in the game and set a record for walks in a four-game series with 13. He scored the Nationals' first run in the third, sprinting from first on Ryan Zimmerman's double that deflected off Bryant's glove and into foul territory.
It's a tough way for the Nationals to finish their 10-game road trip, which started promising with five wins in their first six games before getting swept here.
"I mean, it's doubly tough, especially to play that long and have that many chances and you're sitting on the edge of your seat," Nationals manager Dusty Baker said. "We had opportunities, big time. To lose a game like that, it hurts. But you don't have any choice, really, you gotta lick your wounds and limp back home, then gain some strength when you get back home."
Arrieta was pulled after five innings, matching his shortest outing of the season. The Cubs have won his last 20 starts, extending a franchise record. Chicago is the first National League team since the 1977 Dodgers to start a season with 24 wins in its first 30 games.
"To the last moment, everybody was there to win that game, and that's a beautiful thing," Maddon said.
MOMENTS THAT MATTERED Playmaking: Maddon made the right moves in the seventh. Trailing, 3-1, Maddon let pitcher Trevor Cahill bat for himself, and the right-hander -- a career .102 hitter entering Sunday -- singled up the middle with a hit that knocked Oliver Perez to the ground. Dexter Fowler was hit by a pitch, and both runners advanced on Heyward's sacrifice bunt, the second of his career and first since 2013. Bryant greeted Yusmeiro Petit with a single to center, which tied the game.
"The whole group is complementing each other," Maddon said. "Nobody is worried about credit or other crazy stuff. We're just worried about winning, and that's why we're playing so well."
Pitched around: The Cubs were not interested in allowing Harper to beat them this series. In seven plate appearances Sunday afternoon, Harper was hit by a pitch and walked six times, matching the record for most in a single game. More >
"It's happened before to me -- not at this level, but definitely when I was younger in high school, college, what-not," Harper said. "They had a plan. They stuck with their plan, and unfortunately it worked."
Harper walked 13 times during this four-game series, setting an all-time high for the most walks in a four-game series. Of the 27 pitches Harper saw Sunday afternoon, only two were strikes, and he did not swing at any of them.
"[Because of] how good he is -- why tempt fate?" Maddon said of the free passes to Harper. "If the other guy gets you, that's fine. You have no problem with that."
Start me up: Arrieta did not get a decision, and he is now 22-1 with a 0.92 ERA in his last 27 starts since June 21 of last year. He had trouble with his command, especially his slider. The reigning NL Cy Young Award winner was lifted after throwing 100 pitches over five innings. He gave up runs in three straight innings for the first time in 74 career starts with the Cubs. More >
STRONG RELAY Michael Taylor and Danny Espinosa are two of the Nationals' best defenders with the strongest arms, and they showed them off to extend the game in the 11th. Heyward tried to score from first base after Bryant roped a double into center field, but a strong relay throw from Taylor to Espinosa to catcher Wilson Ramos got Heyward.
"They made a great relay," Maddon said. "They had just put Taylor in the game. He gets that ball and does not fumble it at all."
"Yeah, but when you're a pitcher, you're not just gonna not challenge a guy because of their name and what they can do. You can't play scared. This is a game. It's not, 'Here's your free pass,' you know? Sometimes it calls for that, but I think it's scared baseball." -- Nationals starter Tanner Roark, on the Cubs' decision to walk Harper
In the bottom of the seventh, Bryant was called safe at second on a stolen base. The Nationals challenged the call, and after a review, it was ruled that the call stands.
The Cubs challenged whether Ramos had violated the plate-collision rule when Heyward tried to score from first on Bryant's double in the 11th. After a review, it was ruled that there was no violation and the call was confirmed.
WHAT'S NEXT Nationals: The Nationals return home after a 10-game road trip for the start of a seven-game homestand on Monday against the Tigers at 7:05 p.m. ET. Stephen Strasburg will aim to improve 6-0 for the first time in his career; he owns a 2.36 ERA and 47 strikeouts to nine walks.
Cubs:Jon Lester will open a three-game series Monday at 7:05 p.m. CT against the Padres at Wrigley Field. Lester has gone at least seven innings in four of his six starts this season. He's 0-1 with a 2.92 ERA in two career starts vs. the Padres.