As far as I understood:
Quark confinement states that observing individual quarks is not possible, color charged quarks are confined into hadrons. As we try to pull them apart, force between them increases with the distance and thus more energy is added to the corresponding field. After a point, it is energetically more favorable to create quark antiquark pair instead of stretching the color flux tube more.
My question is that whether the quark confinement mechanism also applies to the quark antiquark pair or not. I would guess it does otherwise it means that we can observe them individually. But it's still better to get a confirmation if I am right or an explanation if I am wrong.