France forward Kylian Mbappe has apologised for missing the decisive spot kick in Monday's 5-4 shootout loss to Switzerland that saw the world champions crash out of Euro 2020.
Two Swiss goals in the final 10 minutes levelled the match at 3-3 to force the last-16 clash in Bucharest to extra time.
Switzerland and France were perfect from 12 yards until the final kick when Yann Sommer saved from Mbappe.
Mbappe, 22, said France were "incredibly sad" after exiting the tournament and that his miss would keep him awake at night.
"I'm sorry about this penalty. I wanted to help the team but I failed," Mbappe wrote on Instagram.
"It's going to be hard to sleep after this, but unfortunately these are the ups and downs of this sport that I love so much.
"The most important [thing] will be to get back up again even stronger for future commitments. Congratulations and good luck to the Swiss team."
French coach Didier Deschamps backed Paris-Saint Germain striker Mbappe and the rest of the team to bounce back and learn from their tournament disappointment
"It will help everyone I think. Kylian, even if he didn't score a goal [at the Euros], he was decisive in many actions that we had, and he took responsibility to take this penalty," he told a news conference.
"No-one is really angry with him. I talked to our players, we know the strength of this team, we've had many magnificent moments together -- today it really hurts, there's lots of sadness," he added.
Deschamps, 52, dismissed suggestions none of Mbappe's teammates went to comfort him after his spot kick was saved.
"The whole group is united in the dressing room. No-one talks about 'you made this mistake' or 'you made that mistake', Kylian knows his responsibility," added Deschamps.
France were 3-1 up and cruising with 15 minutes to go after a superb goal by Paul Pogba, but the dogged Swiss scored twice to force extra time before eventually going through to face Spain in the quarter-finals in St Petersburg on Friday.
"Today we were against a strong Swiss team, they gave us some problems in the first half, and of course France is used to having compact opponents," Deschamps explained.
"We scored our second goal in the second half which changed everything and, if you want, 10 minutes before the end we could have managed our two-goal advantage better."
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Switzerland manager Vladimir Petkovic and captain Granit Xhaka hailed their achievement as they reached the last eight of a major tournament since they hosted the World Cup in 1954.
“No normal side would have come back from 3-1 down against the world champions,” said Petkovic, who equalled the record for the most matches in charge of the Switzerland team.
Xhaka said they had written a new chapter, which was particularly satisfying after the stinging criticism that followed their 3-0 loss to Italy in Rome on June 16 in their second Group A match.
“I’ve always said this team deserved a lot more than you can read," he told the post-match news conference.
"There was so much discussion about this team. They said we were arrogant but I can guarantee you one thing, we really wrote a history. All Swiss people can be really proud. We achieved something that is impossible to describe with words."
Trailing 1-0 at the break, after a disjointed and dispirited first-half display, France were staring at a 2-0 scoreline before goalkeeper Hugo Lloris saved Ricardo Rodriguez's penalty.
That reprieve prompted a blistering response with Karim Benzema scoring twice and then Paul Pogba scoring a 75th-minute screamer to make it 3-1.
Game over, many of those watching would have felt, but from the way they played, the French too made the fatal mistake of under-estimating the Swiss, who forced the game into extra time through Haris Seferovic's second and then a 90th minute equaliser from Mario Gavranovic.
"Nobody believed in us any more at that stage," said goalkeeper Sommer.
"We felt they had become a bit complacent and maybe thought they had already won it. So we used that to our advantage."