I think Navi wins in a close game, fpx already beat optic. Nrg are having rough games, nrg seem to have the same problems as optic of starting slower. So I think it can definitely swing into Navis favor.
It's not a rematch tho, these are new teams and nrg seem to exhibit the same issue of starting slow. They probably still qualify but I have faith in Navi to make it out of groups as first seed.