Of course I believe it
Not saying that for sure Slovakia will go through (although I hope it), but if you've got 3 points after two matches, you simply are not at all out yet, no matter how you look at it
I mean, there's two groups where 3rd place only has a single point and another group where they have 2 points, and not all groups are done with their second round of matches yet. Right now, 16 teams played two matches and roughly half of them are already in a worse position than Slovakia is, which will be even more after tomorrow.