SANTA CLARA, Calif. >> The New York Giants kept dialing up blitzes and the San Francisco 49ers just got the ball into their playmakers’ hands.

Christian McCaffrey scored a touchdown in his 12th straight game, Deebo Samuel caught one of Brock Purdy’s two TD passes and the San Francisco 49ers won their 13th straight regular season game, 30-12 over the New York Giants on Thursday night.

“They got a good bit of pressure on Brock and caused a couple of three-and-outs but it’s about how long you can sustain doing that,” Samuel said. “So in the second half we came out executing.”

The Niners weren’t particularly sharp on offense early in their home opener but got enough from McCaffrey and on big runs after the catch by Samuel and George Kittle to earn their second 3-0 start in 25 seasons.

The Giants blitzed Purdy on 33 of his 39 dropbacks, according to NFL NextGen stats, and he capitalized with 247 of his 310 yards passing on those plays, including the touchdowns to rookie Ronnie Bell and Samuel.

“I thought it was just a huge challenge, one of the bigger ones Brock has been in with a short week to prepare for a scheme like that,” coach Kyle Shanahan said. “There’s not a comfortable play throughout the game. … I thought he settled down as the game went on.”

McCaffrey ran for 85 yards, added 34 more receiving and scored on a 4-yard run that made it 17-3 late in the second quarter. That matched Jerry Rice’s franchise record with 12 straight games in the regular season or playoffs with a TD and is three shy of the NFL mark.

The defense did the rest against the short-handed Giants (1-2), who fell behind by double digits at the half for the third time in three games this season.

With the running game hampered by the absence of injured star Saquon Barkley and the offensive line overmatched without left tackle Andrew Thomas and left guard Ben Bredeson, the Giants struggled to move the ball and finished with 150 yards of offense.

“No excuses with anybody who missed the game or who played,” coach Brian Daboll said.

They managed two field goals in the first half and scored on Matt Breida’s 8-yard run on a third-quarter drive that needed just 15 yards thanks to two penalties on the Niners.

Daniel Jones was often on the run and couldn’t get anything going downfield. He went 22 for 32 for 137 yards and an interception.

“We didn’t create a rhythm,” Jones said. “We didn’t execute, didn’t take advantage of our opportunities, That’s a good defense, a good team and when you are playing good teams you can’t afford to do that. We didn’t play well enough.”

GOOD FORTUNE

Purdy was off target in the first half but his numbers were pretty good thanks to some fortunate bounces and help from his teammates. Kittle broke up a potential interception on the opening drive and Purdy had another pass to Samuel that got deflected and bounced high in the air before Bell caught it for a 15-yard gain.

Purdy also converted a third-and-15 and third-and-13 on the same drive by throwing quick passes behind the line of scrimmage that Samuel and McCaffrey turned into first downs.

SLOW STARTS

The Giants once again found themselves in a big hole at halftime, trailing 17-6. It was an improvement from the first two weeks when they trailed Dallas 26-0 in the opener and Arizona 20-0 in Week 2. They rallied to beat the Cardinals with a strong second half.

New York also got down 28-0 in a playoff loss last season to the Eagles, marking the first time since 2003-04 that they trailed by double digits at the half in four straight games.

SCUFFLE

There was a small scuffle late in the first half when the Niners were trying to take a knee to run out the clock. San Francisco left tackle Trent Williams took offense when New York’s A’Shawn Robinson shoved Aaron Banks and Williams shoved him with two hands. Robinson appeared to throw a jab toward Williams, who then responded with a punch to the facemask.

Offsetting penalties were called but Williams was not ejected.

“We ended up looking at the video we had available to us, and we just didn’t see anything that rose to the level of flagrant, which is the standard that we have to apply to disqualify the player,” NFL Senior Vice President of Officiating Walt Anderson told a pool reporter.

INJURIES/INACTIVES

Giants: Rookie CB Deonte Banks (arm) and DL D.J. Davidson (elbow) left in the second half.

49ers: WR Brandon Aiyuk (shoulder) missed his first game since his rookie season. … CB Ambry Thomas (knee) also was inactive.

UP NEXT

Giants: Host Seattle on Monday, Oct. 2.

49ers: Host Arizona on Oct. 1.