LANDOVER, Md. — It was the Eli Manning-to-Larry Donnell show Thursday night.

New York’s veteran quarterback connected with his new starting tight end for three touchdowns in the first half, and the Giants whipped the turnover-riddled Washington Redskins 45-14 in an NFC East battle at FedEx Field.

Manning completed 28 of 39 passes for 300 yards with four touchdowns and an interception in New York’s second consecutive victory after a 0-2 start.

“His confidence has risen and his confidence in his team has risen,” Giants coach Tom Coughlin said of Manning and the quarterback’s development in new coordinator Ben McAdoo’s offense.

While Manning was soaring, Redskins quarterback Kirk Cousins (19-for-33, 257 yards, one touchdown) threw four interceptions and lost a fumble after consecutive 400-yard outings against the Jacksonville Jaguars and Philadelphia Eagles. Washington backup tight end Logan Paulsen contributed the sixth turnover.

“It felt like Christmas,” Giants safety Antrel Rolle said of going against Cousins.

“We were abysmal offensively and defensively,” said Redskins coach Jay Gruden, whose team fell into the NFC East basement at 1-3. “(Kirk) was trying to create a spark, and there was no spark there and he just forced a few throws. By no means can we put the blame on Kirk for this game. This was a total team debacle.”

Manning connected for a 5-yard touchdown to Donnell 7:25 into the game, six plays after defensive end Mathias Kiwanuka sacked and stripped Cousins and New York defensive tackle Cullen Jenkins at the Washington 24. The touchdown represented the Giants’ first points in the first quarter this season.

New York’s fourth possession began at its 25-yard line. Washington cornerback E.J. Biggers, on the field only because DeAngelo Hall sustained a season-ending torn Achilles tendon last week, let Giants receiver Victor Cruz (six catches, 108 yards) run free for a 36-yard catch. Five plays later, Donnell out-jumped Meriweather to grab a 6-yard touchdown from Manning just 46 seconds into the second quarter.

With the Redskins down 14-0, Cousins engineered a 10-play, 80-yard drive.

Manning responded with a 12-play, 67-yard march that ended with Donnell’s 6-yard grab against rookie cornerback Bashaud Breeland. That catch made Donnell, who only had three receptions last season, the first Giants tight end with three touchdowns in a game since Joe Walton in 1962.

Giants kicker Josh Brown’s 29-yard field goal that made it 24-7 as the half ended.

A 36-yard screen to backup running back Roy Helu Jr. preceded starter Alfred Morris’ 20-yard run untouched to the end zone that shaved the Redskins’ deficit to 24-14 just 2:03 into the second half.

What the Giants said:

“We give him a pocket, he’s going to show off.” — Left tackle Will Beatty on quarterback Eli Manning.

“They all tie into each other so every time I think about one I just smile from ear-to-ear.” — Tight end Larry Donnell on his three-touchdown night.

What the Redskins said:

“Sometimes a good slap in the face … is what you need and hopefully our guys respond.” — Coach Jay Gruden after the 45-14 shellacking.

“Tonight we wouldn’t have beat anybody. We wouldn’t have beat William & Mary. We wouldn’t have beat Virginia Tech, any other team close to here that they could’ve picked to play us, a high school team ranked in the top 10, we wouldn’t have beat them.” — Safety Ryan Clark.

What we learned about the Giants:

1. Eli Manning can run new coordinator Ben McAdoo’s offense. After going 44-of-72 for 440 yards, three touchdowns and four interceptions in the first two games, Manning is 49-fo-67 for 534 yards, six touchdowns and a pick the last two games.

2. The defense can make big plays. After forcing just three turnovers in their first three games, the Giants caused six Thursday night

–MLB Jon Beason is sidelined with foot and toe injuries so Jameel McClain moved inside from the strong side and Mark Herzlich took McClain’s spot. .

–TE Larry Donnell, who only had three receptions last season, became the first Giants tight end with three touchdowns in a game since Joe Walton in 1962.

–QB Eli Manning threw four touchdown passes after throwing just 16 in his previous 20 games against Washington.

What we learned about the Redskins:

1. For all the excitement about Kirk Cousins after his consecutive 400-yard games, he has 15 interceptions and four lost fumbles in 11 career games.

2. Washington’s defense might not be improved after all. After allowing just 20 points (not counting a blocked punt) against AFC foes Houston and Jacksonville, the unit was torched for 75 points (not counting a kickoff return) by division rivals Philadelphia and the New York Giants.

–P Tress Way’s 58.3-yard average on his four punts was second in franchise history to Hall of Famer Sammy Baugh’s 59.4-yard average against Detroit on Oct. 27, 1940. Way’s 77-yard punt in the third quarter was tied for the third-longest in Redskins history.

–TE Niles Paul’s three catches for 60 yards made him the first Redskins TE with at least 60 receiving yards in four straight games since Chris Cooley in Weeks 11-14 of 2007. Paul had just 228 receiving yards during his first three seasons combined.

–LG Josh LeRibeus made his first career start in his third season with LG Shawn Lauvao sidelined with a knee injury.

–S Ryan Clark was credited with 14 tackles, the most of his 13 seasons. Clark’s previous high of 13 came last season against Tennessee when he was playing for Pittsburgh.