Arrieta (17-6) became the first 17-game winner in the big leagues by throwing baseball's third no-hitter in less than three weeks.
Astros right-hander Mike Fiers blanked the NL West-leading Dodgers 3-0 on Aug. 21. Los Angeles had never been no-hit twice in a season.
Arrieta struck out a season-high 12 — one off his career high — and walked one to help the Cubs snap a four-game skid on the last night of their six-game West Coast trip. He finished August with a 6-0 record, tying Boston's Joe Kelly as the only pitchers with that many wins in the month.