It is Enzo Fernandez and not Moises Caicedo who will continue Chelsea's representation at the Copa America after Argentina dramatically defeated Ecuador on penalties in Thursday's quarter-final in Houston.

Enzo and Caicedo went toe-to-toe in central midfield while Kendry Paez, who will join Chelsea after his 18th birthday next year, once again started on the right wing for Ecuador.

Caicedo had a good chance inside six minutes when he found himself through on goal. With Argentinean defenders recovering, he got his shot away under pressure with Emiliano Martinez getting down low to save.

Caicedo, deployed as the more advanced of Ecuador's three central midfielders, then did brilliantly down the left before crossing low to Brighton's Jeremy Sarmiento, who was also denied by Martinez. Paez fired over from the follow-up, again picked out by Caicedo.

Argentina were on the back foot but did threaten seriously for the first time in the 27th minute when Enzo, arriving late in the penalty box, headed just wide from a teasing right-wing cross.

It was the world champions who took the lead nine minutes later when Lautaro Martinez headed in a flicked-on Lionel Messi corner at the far post.

Ecuador had a golden chance to equalise on the hour. A Caicedo corner was handled by Rodrigo De Paul but Enner Valencia couldn't capitalise, sending Martinez the wrong way but hitting the post with his spot-kick.

Enzo was withdrawn in the 78th minute, just after Paez had made way for Alan Minda. Ecuador kept plugging away and got their reward in the first minute of stoppage time, substitute Kevin Rodriguez glancing in a fine header.

The match went straight to penalties and the shoot-out started with a Messi miss, his attempted Panenka hitting the crossbar.

But Martinez superbly saved Ecuador's first two penalties to put Argentina in the driving seat, and they were flawless with their remaining four spot-kicks to secure their progression to the semis. Ecuador bow out heartbroken but with their heads held high.

Argentina will play Venezuela or Canada in the semi-final in New Jersey on Tuesday night local time.