The much younger, faster and less worn out looking England side continued to cause Croatia problems going forward and also doubled their lead but a great Danijel Subasic save kept it at 1-0.
With his first global goal, just over a year after his England debut, the 27-year-old Trippier joined David Beckham as the only English players since 1966 to score on free kicks at the World Cup.
But Ivan Perisic grabbed the equaliser in the 68th minute, getting an outstretched boot to Sime Vrsaljko's cross and guiding the ball past England goalkeeper Jordan Pickford. "They've shown remarkable character", said England coach Gareth Southgate, who for now will be remembered more for a fashionable waistcoat than ending a half-century of hurt.
He said: "It was a tough, 50-50 game".
"We still have lots of energy in the tank", he said.
As the first half progressed, and with England dominant, the opportunity was there to put the game away.
Josip Pivaric of Croatia celebrates his Fifa World Cup semifinal win over England.
"It's been great to get to this stage and we know we've done everyone proud but we wanted to go on and win it", Kane added.
"I have been in sport in different areas for long enough to know what my life is day to day".
Kane had lead England to their first World Cup semi-final since the Italia '90 tournament 28 years ago, and in doing so scored a record amount of goals.More news: Trump pressures NATO members to spend 2% of GDP on defense ‘immediately’
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One team had yet to compete in a World Cup final, the other had last won it all way back in 1966, and hadn't made it to the semifinals in close to three decades.
"They have taken the nation with them". The Croatian striker drifted in behind the England defence, who weren't aware of his presence, and he spun to take the shot on the swivel, firing a low finish past Pickford.
"During half-time, I told the players "calmly pass the ball, do not lose your heads".
What is not in doubt is their quality.
Croatia's best chance of the half came in the 31st minute when Modric squared back to Rebic inside the box but his left foot shot was saved by Pickford. And they were down against England in the semifinals and advanced.
Instead of attempting to kill the game off with a second goal, England retreated and allowed Croatia's midfield ball players, Luka Modric, Marcelo Brozovic and Ivan Rakitic to wrestle control of the game.
Vrsaljko cleared a John Stones header off the line midway through the first extra period.
The score was precariously-poised at 1-1 at the end of 90 minutes, so the match went into extra-time.
Gareth Southgate's team opened the scoring at the Luzhniki Stadium, but Croatia turned things around and will now face France in Sunday's showpiece finale.
Croatia have never been to a World Cup final, though they reached the semi-finals in 1998 with a team featuring the likes of Slavan Bilic and Davor Suker.