The France midfielder has revealed he went into the dressing room after the game to say sorry to the Lazio star for a tackle that ended his match
Just before an hour had been played, the Paris Saint-Germain midfielder challenged the Lazio player in the centre of the field but was late to the ball and caught Onazi on the ankle – a blow that ended the 21-year-old's involvement and left Nigeria boss Stephen Keshi fuming.
Matuidi, who was only shown a yellow card for the tackle, has confessed that the challenge was a poor one but has protested that there was no intent to injure the Super Eagles man.
"I'm sorry," he told the media after the game. "I've not gone in to hurt him; I'm disappointed because I'm not a dirty player.
"I went into the [Nigeria] dressing room afterwards to apologise."
The PSG star had praise for the spirit of his side, who had spent much of the opening hour under pressure from their opponents before Paul Pogba's header and Joseph Yobo's own-goal sealed the win.
"We may not have the talent of previous generations but we have the heart and the mind," he said. "This is what has put us [in the quarter-finals]."
For midfield partner Pogba, the 27-year-old only had words of admiration.
"He has a great future and he showed that today," the Toulouse-born added stated.
Matuidi has 26 caps for France, which he will be aiming to add to when they meet either Algeria or Germany in the quarter-finals on Friday.