- Lionel Messi (34' Pen)
- Julián Álvarez (39', 69')
Messi opened the scoring with a powerfully hit penalty on 34 minutes -- becoming Argentina's all-time leading goal scorer at World Cup finals -- and shortly after Alvarez completed a direct solo run through the heart of the Croatia defence before tapping home to double Argentina's lead before half-time.
Alvarez added the side's third, thanks in part to a signature run from Messi who used his change of speed to guide past Josko Gvardiol before sliding the ball back to Alvarez for an easy finish.
Croatia, who finished runners up in Russia four years ago, exit the competition after putting together another shock run to the semifinals.
"Throughout the World Cup it has been incredible what we have experienced. We are going to play the final which is what we wanted," Messi said.
"I don't know if it's my best World Cup, it's been a long time I've been enjoying. This team is crazy. We are going to play one more final, we are going to enjoy all of this."
Messi's inclusion in the starting lineup meant he drew level with Germany's Lothar Matthaeus as joint record holder for most World Cup appearances with his 25th game.
Croatia wanted possession at the start, as they had done against Brazil in their quarterfinal, and circulated the ball well but struggled to find a way into the Argentina box.
Argentina enjoyed a prime chance to take the lead when Alvarez was brought down by Croatia goalkeeper Dominik Livakovic in the box for a penalty, with Messi on hand to convert.
But the best was yet to come and it was Alvarez again involved as he picked up a Messi pass in his own half, sprinted 50 metres and weaved his way into the Croatia box, thanks to two lucky bounces and some sloppy defending, before tucking in the second goal.
Livakovic, who had carried Croatia into the semifinals with saves in their penalty shootout wins against Japan and Brazil, did well to stop an Alexis Mac Allister header on the stroke of half-time that could have killed off the game after 45 minutes.
However, unlike their extra-time comeback heroics against tournament favourites Brazil, there was no way back this time for Croatia.
Argentina were in no mood to squander their two-goal advantage as they had done against the Netherlands in the last eight, and they conceded no space.
Alvarez dashed any lingering Croatia hopes in the 69th, tapping in a cutback after Messi tricked his way past defender Gvardiol on the right to pick out his teammate in the box who sealed Croatia's tournament exit.
"We have gone through some tough situations, some very good ones," Messi added. "Today we are experiencing something spectacular.
"I'm enjoying it with all these people and with all the Argentinians who are in our country. I imagine it must be crazy."
Information from Reuters contributed to this report.
- Daniele Orsato