Lionel Messi was fearful ahead of his return to action for Argentina at the Copa America.

Messi sat out Argentina's win over Peru in the group stage, but despite Lionel Scaloni saying the eight-time Ballon d'Or winner was a doubt to feature against Ecuador in the quarters, he started on Thursday.

The 37-year-old had just 32 touches in a 1-1 draw, marking his fewest touches in a competitive match for his country in which he has played 90 minutes since 2011.

Messi subsequently missed his penalty in the shootout, but goalkeeper Emiliano Martinez spared his blushes in a 4-2 victory for the defending Copa America champions.

When asked how he had been feeling ahead of the tie, Messi told reporters (via The Athletic): "The truth is bad.

"With a lot of uncertainty, with lots of fear when I was training, a lot of desire to be here and doing everything possible to be able to play.

"I was able to be here and [help] the team."

Messi explained it was no surprise to Argentina that they faced such a stern challenge from Ecuador.

"The truth is it was a difficult match, which was very hard to play," Messi added.

"We knew it was going to be that way because they’re a great team, a hard team who press well, who have intense, dynamic players, and when they have the ball they do damage as well.

"We expected this kind of game."

Argentina have now extended their unbeaten streak against Ecuador to 17 matches at the Copa America (W11 D6). This is the third longest unbeaten run for La Albiceleste against a single opponent in the competition, following a 30-match run against Chile (W22 D8, excluding penalty shootouts) and 26 against Paraguay (W20 D6).

Messi and Co. will face either Canada or Venezuela in the last four.