Betts not only set the Dodgers' record for leadoff home runs with 29 - breaking a tie with Davey Lopes - he moved past Ian Kinsler and into sole possession of fifth place on MLB's all-time list with 49 in 11 seasons. Miguel Rojas added a homer for Los Angeles.
Right-hander Bobby Miller (1-0) had a career-best 11 strikeouts over six innings. He gave up two hits with one walk. Evan Phillips pitched a scoreless ninth inning for his second save.
Nolan Gorman drove in two runs, while left-hander Zack Thompson gave up five runs in 5 1/3 innings for the Cardinals, who are 0-2 after going 71-91 last season for their worst record in a 162-game season since 1990.
Brewers 3, Mets 1
Freddy Peralta and a trio of relievers combined on a one-hitter and Christian Yelich had three hits, including a solo homer, as Milwaukee beat hosts New York in the season opener for both teams.
Yelich homered in the fourth inning for the Brewers to tie the game at 1-1. Milwaukee added runs on William Contreras' tie-breaking sacrifice fly in the fifth and rookie Jackson Chourio's RBI fielder's choice in the seventh. Chourio, who is 20 years and 18 days old, batted leadoff and went 1-for-3 with a single, a walk and a stolen base.
Peralta (1-0) went six innings, giving up only Starling Marte's line-drive homer in the second inning. He walked one and struck out eight. Jose Quintana (0-1) allowed two runs on six hits and two walks while striking out four over 4 2/3 innings.
Braves 9, Phillies 3
Matt Olson had three doubles and three RBIs, Michael Harris II added three hits and an RBI and Atlanta defeated hosts Philadelphia on Opening Day for both teams.
Orlando Arcia compiled three hits, Ronald Acuna Jr. added two hits and an RBI and Adam Duvall produced a two-run, pinch-hit double. Braves starter Spencer Strider allowed three hits and two runs with eight strikeouts and two walks in five innings. Pierce Johnson (1-0) earned the win in relief.
Brandon Marsh hit a two-run home run and Alec Bohm had two hits for the Phillies. Philadelphia starter Zack Wheeler tossed six scoreless innings and gave up five hits with five strikeouts and no walks. Jose Alvarado (0-1) allowed five runs on three hits and two walks in just two-thirds of an inning.
Mariners 1, Red Sox 0
George Kirby allowed just two hits over 6 2/3 scoreless innings and J.P. Crawford homered as Seattle edged visiting Boston.
Kirby (1-0), a right-hander, walked two and struck out eight. Reliever Andres Munoz got the final four outs for his first save, striking out the side in the ninth. Crawford went deep off Red Sox starter Pivetta (0-1) with one out in the bottom of the sixth, hitting a cut fastball on an 0-1 count just inside the right-field foul pole.
It was the third and final hit Pivetta allowed in his six innings, following a two-out single by Ty France in the second and a leadoff single by Julio Rodriguez in the fourth. Pivetta didn't walk a batter and struck out 10.
Guardians 6, Athletics 4
Andres Gimenez had three hits and scored two runs for visiting Cleveland in a win against Oakland in the second game of their four-game series.
Jose Ramirez hit a two-run homer, Steven Kwan had two hits and two runs scored and Josh Naylor had two hits and a run for the Guardians, who won the season opener 8-0 on Thursday. Cleveland starter Logan Allen (1-0) allowed three runs and six hits in five-plus innings.
J.D. Davis homered twice and Shea Langeliers and Nick Allen had two hits each for the A's. Oakland starter Ross Stripling (0-1) allowed five runs (four earned) and seven hits in five innings. He struck out six and walked two.
