Cubs walk it off in 13 — and win 20th in a row when Jake Arrieta starts

Jake Arrieta's unbeaten streak lives - with an awful lot of help from his friends.

But the Cubs rallied to tie the game in the seventh, and in the bottom of the 13th inning, Javier Baez ripped a walk-off homer off Nationals reliever Blake Treinen for a 4-3 victory and four-game sweep. The Chicago Cubs right-hander and reigning Cy Young Award winner battled command issues and his own poor fielding and left the game after five innings with the Cubs trailing the Washington Nationals by two runs.

And so, the Cubs won their 20th consecutive game started by Arrieta. He became just the sixth pitcher since 1913 whose team won at least 20 of his starts in a row.

This one, however, was almost in spite of Arrieta rather than because of him.

He came in riding perhaps the greatest 26-start run in baseball history: A 22-1 record, a 0.85 ERA and 184 strikeouts to just 39 walks since June 21.

But a rash of recent command problems dogged Arrieta once again. For the third time in his past four starts, Arrieta issued four walks. While one of those outings resulted in his second no-hitter since August, it suggested that, even as he won his first six starts this season, his peerless command might be slipping.

Sunday seemed to bear that out. In addition to his four walks, Arrieta uncorked three wild pitches and gave up six hits in five innings before he was removed for a pinch hitter and the Cubs trailing 3-1.

Kris Bryant got him off the hook, though, with a game-tying two-run single in the seventh. Meanwhile, the Cubs bullpen pieced together eight scoreless innings - three from Trevor Cahill, two each from Adam Warren and Justin Grimm and one from Travis Wood - to keep the Nationals at bay.

And Baez's no-doubt shot to left center field pushed Arrieta's remarkable streak to 20.