Harry Kane scored twice in the first half as England eventually saw off Croatia 4-2 to launch their World Cup title assault in Texas on Wednesday.
Jude Bellingham, immediately after half-time, and substitute Marcus Rashford with five minutes to go ensured a winning start for Thomas Tuchel's side after Croatia had fought back to level at 2-2.
The prolific Kane twice put England ahead in the first half -- one a retaken penalty -- only for Martin Baturina and Petar Musa to hit back for 2018 runners-up Croatia.
With both sides shaky at the back, the second half threatened another goal glut, Bellingham needing just two minutes to put England ahead again in front of a crowd of 70,000.
England had numerous chances to extend their lead but did not take them until Rashford popped up to put the seal on a chaotic encounter.
"I thought the game was two halves really," the skipper Kane told ITV.
"I thought first half we were okay. Really disappointed to concede in the way we did, the way we dropped off.
"And credit to the manager. The manager gave us a speech at half-time just to say, look, if we lose, we're losing our way.
"And I think you saw that, the way we come out in the second half, we went full gas, and they couldn't live with it."
The meeting was a repeat of the 2018 semi-final, which Croatia won after extra-time, although England have since had the edge against one of the older squads in North America.
Zlatko Dalic, the Croatia coach who has masterminded much of their recent success, said England's prowess at dead-ball situations had caused numerous problems.
He called it a "strange and difficult" match.
"We made a lot of mistakes, especially when it came to set-pieces," said Dalic, whose side face Panama next and will still fancy their chances of getting out of Group L.
England play Ghana next.
Tuchel's side, bidding to deliver England a first major trophy since 1966, made a nervy start at the impressive air-conditioned home of the Dallas Cowboys.
Then the drama came. Croatia's talismanic captain Luka Modric dangled out a leg and caught Noni Madueke in the box.
Kane saw his unconvincing penalty saved by Dominik Livakovic, only for French referee Clement Turpin to order a retake after video replays deemed the stopper had come off his line.
Bayern Munich predator Kane held his nerve second time around, again going to Livakovic's left but this time in more ruthless fashion to give England the lead after 12 minutes.
Now it was all England, and Real Madrid midfielder Bellingham -- preferred to Morgan Rogers in the number 10 role -- surged upfield, forcing Livakovic to smother.
On 36 minutes Croatia drew level.
England squandered the ball in midfield, then Petar Sucic left John Stones on the floor with some neat footwork to set up Baturina.
The 23-year-old met the ball first time and whipped it past Jordan Pickford.
Croatia were level for just six minutes as a Declan Rice corner found Kane unmarked and the captain nodded home.
It took Kane to 10 World Cup goals, the most of any England player along with Gary Lineker.
Tuchel, who has made it clear that winning the World Cup is his aim, barely smiled.
Putting the seal on a frenetic first half, Musa took advantage of more poor England defending in the fifth minute of injury time to stroke the ball in for 2-2.
The second half started just as the first ended as Bellingham galloped down the right unchallenged and rolled the ball into the corner.
Kane and Nico O'Reilly twice each, and Bellingham, had good chances for a 4-2 lead as England pummelled the Croatia goal.
With 15 minutes left and England retreating, Croatia had several opportunities, before Rashford made the three points safe.
"Just the intensity we went at, I think that's our biggest strength," Kane said, when asked what was different in the second half.
"So we're going to have to use that more at this tournament."
He added: "Once we went ahead we never really looked like we were in danger."
pst/nf
