Lewis Ferguson has said he was left with a feeling that Scotland "let ourselves down a bit" after their World Cup Group C campaign.
A 3-0 defeat by Brazil in Miami left Steve Clarke's side with three points and a -3 goal difference.
Their chances of qualifying as one of the eight best third-placed teams have since grown increasingly unlikely with Scotland on the worst record among their rivals after half of the 12 groups had completed.
Ferguson has arguably been Scotland's brightest performer in a tournament that opened with a 1-0 win over Haiti and continued with a 1-0 loss to Morocco.
But the Bologna midfielder, who returned to Scotland's base camp in Charlotte, North Carolina, said: "I think we just let ourselves down a bit.
"It's going to be nervy watching some of the games and looking out for the results, and that's not what we want, that's not the position we want to be in.
"We wanted to do it on our part and get the points necessary. Now we need to wait and hope for other results to go our way, and whether that's the case or not, it's just a waiting game.
"This is the time for the more experienced lads to get around everybody, and I think we've got those kind of guys within the squad that can do that and can lift the spirits.
"We've got a couple of days now, and we'll need to try and build that positivity back up."
Ferguson spoke of overriding emotions such as hurt, anger and frustration after defeat in Miami.
The former Hamilton and Aberdeen midfielder added: "We wanted to go and give ourselves a chance to get through, we've done that by getting the three points, but I think the last two games we probably let ourselves down a little bit.
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"We wanted to get better results, albeit we are coming up against some top-level sides and it is really difficult. But I had full belief that we've got the quality within our squad to get results against these kind of teams and, sadly, we've just come out short.
"That first three points might come in handy, but just the feeling right now is that you know the goal difference probably doesn't stand us in good stead."
If Scotland were to get through to the knockout stage for the first time, Ferguson admits improvement would have to be wholesale to have any chance of further progress.
He said: "I think we've showed in spells that we can be a really good team but we've never quite just had that proper 90-minute performance, which we're going to need if we do get through the knockout stages.
"There are no second chances there. You need to be on it for the full 90 minutes, and any sort of slip of any mistake can cost you, especially at this level.
"We need to improve. We know we need to improve in a lot of aspects.
"We'll try and put those things right over the next few days, and if we do get the chance to get into the next round, then we need to be better if we're going to progress again."