Cubs 4, Nationals 3 (13)
CHICAGO -- Chicago Cubs ace Jake Arrieta had a rare off day against the Washington Nationals. But his team rallied for yet another victory.
Javier Baez homered in the 13th inning as the Cubs beat the Nationals 4-3 on Sunday. The Cubs swept the Nationals in four games and extended their season-high winning streak to seven.
Chicago has the majors' best record at 24-6 while the Nationals are 19-12.
Arrieta -- the reigning National League Cy Young winner -- allowed three runs (two earned) and six hits in five innings in a matchup of the league's top teams. He struck out seven, but walked four (one intentional), threw three wild pitches and committed a fielding error. His 0.84 ERA that led all of baseball rose to 1.13.
Kris Bryant's two-run single tied the game 3-3 in the seventh, preventing Arrieta's first loss since July 25.
The Nationals loaded the bases in the 10th on a single and two walks (one intentional to Bryce Harper), but Ryan Zimmerman flew out to end the threat. The Cubs also threatened in the inning, putting two on before Javier Baez flew out.
Jason Heyward reached on an infield single and tried to score on Bryant's double in the 11th but was thrown out at the plate.
In the 12th, the Cubs walked Harper for the sixth time -- tying the major league single-game record -- to load the bases before Zimmerman grounded out.
While Arrieta faltered, Washington starter Tanner Roark struck out seven and allowed four hits and an unearned run in six innings.
Daniel Murphy doubled and scored on Wilson Ramos' single for a 3-1 Nationals lead in the fifth.
The Cubs cut the lead to 2-1 in the fourth via an error, two groundouts and a wild pitch.
Anthony Rendon's bases-loaded groundout scored a run for a 2-0 Washington lead in the fourth.
Harper scored from first on a Zimmerman double off third baseman Bryant's glove for a Nationals' 1-0 lead in the third.
NOTES: The Cubs activated RHP Neil Ramirez (0-0, 4.50 ERA) from the bereavement list on Sunday. To make room for Ramirez, the Cubs optioned RHP Spencer Patton to Triple-A Iowa after Saturday's game against the Nationals. Patton allowed a run without recording an out in his one appearance. ... Cubs C Miguel Montero felt good and had no issues increasing his hitting on Sunday, manager Joe Maddon said. Maddon has no timeline for Montero's return. He went on the disabled list April 25 for lower-back tightness. ... Nationals 2B Daniel Murphy returned to starting lineup Sunday after he was out of the lineup Saturday due to an illness. He did pinch hit Saturday.