Betts went 4 for 4 with a home run and the Dodgers took advantage of a high throw by first baseman Pete Alonso to beat the sloppy Mets 5-1 on Saturday night for their sixth straight victory.
"I think this lineup top to bottom, they all swing it really well. And I think it was just a matter of time before we started clicking and started rolling," Los Angeles pitcher Tony Gonsolin said.
Max Muncy scored the tiebreaking run in the eighth inning on David Peralta's RBI grounder. Alonso, who moments earlier made his second diving play of the night, had a chance to start an inning-ending double play - but his throw to second base forced shortstop Francisco Lindor to make a leaping grab and then find the bag, giving Peralta enough time to beat the relay back to first.
"Just wish I could have executed a little bit better," Alonso said.
Los Angeles added three insurance runs in the ninth, the first scoring when rookie third baseman Brett Baty misplayed a high popup for an embarrassing error. To make matters worse, the ball bounced up and dinged Baty right in the face after he made a desperate, staggering dive.
"I actually thought I was going to catch it in foul ground and then took my eye off of it for one second and kind of got spun around," Baty said. "But there's no excuse for that. That play needs to be made."
Brandon Nimmo homered for the Mets, held to three hits one night after mustering just one - Nimmo's leadoff double - in a 6-0 loss to the Dodgers. All-Star rookie Kodai Senga struck out nine in six innings of one-run ball, but New York (42-50) dropped its fourth in a row following a six-game winning streak.
"Extremely frustrating, for sure," Alonso said. "We had some opportunities, especially there late in the game."
Brusdar Graterol (3-2) worked a hitless seventh for the NL West leaders, who have won 14 of 19.
New York put runners at the corners with none out in the eighth, but Caleb Ferguson retired pinch-hitter Mark Canha on a foul popup and then struck out Baty and Luis Guillorme on seven pitches to preserve a one-run lead.
"I got a little too overanxious. He's a good arm, for sure," Baty said.
Baty whiffed all three times up. Adam Ottavino (0-4) took the loss.
Gonsolin limited the Mets to two hits through five innings on a season-low 54 pitches. With a string of left-handed hitters coming up on a humid night, he was lifted by manager Dave Roberts for left-hander Alex Vesia.
"I can see where he's coming from, for sure. But I wanted to stay out there one, two more innings at least. I was pretty efficient," Gonsolin said.
It was the fewest pitches needed by a Dodgers starter to complete five innings since Greg Maddux threw 47 over six innings in the final game of his Hall of Fame career on Sept. 27, 2008.
Betts homered in the third on a 97 mph, 2-2 fastball from Senga. The 344-foot drive bounced off the top of the fence in the right-field corner for his 27th homer, eighth in 13 games - and first all season to the opposite field.
"I know I can do it. I just don't. I mean, I guess," Betts said. "But it just means we're in a pretty good spot."
Betts is batting .410 with 21 RBI in his last 17 games, and his 10 homers since June 23 are the most in the majors.
"I think I finally found a mechanical cue and a mechanical feel that sticks, that I'm able to repeat over and over again that works," Betts said.
Nimmo answered by leading off the fourth with a 445-foot shot to center, the second-longest of his career. It was his 14th homer this season and 10th since June 8.
The start was delayed 46 minutes with rain in the area. Under a darkening sky, injured Dodgers pitcher Clayton Kershaw and three young kids played with a bucket of baseballs in foul territory, a few feet from the tarp covering the infield.
Dodgers: After getting through a simulated game without issue, Noah Syndergaard was sent to Triple-A Oklahoma City on a rehab assignment. Roberts, however, said he didn't know when the right-hander is supposed to pitch. Syndergaard (index finger blister) was placed on the injured list June 8 for a reset after going 1-4 with a 7.16 ERA in 12 starts.
Mets: RF Starling Marte was scratched from the original lineup because of vomiting and wasn't available off the bench. ... RHP Sam Coonrod has progressed to throwing bullpens. The reliever has been sidelined all season by a right lat strain.
Dodgers rookie Bobby Miller (5-1, 4.50 ERA) makes his ninth major league start in the series finale Sunday, though rain is in the forecast. After shaking off a stiff neck, Mets RHP Max Scherzer (8-3, 4.31) faces his former team.