This game is way more important than Barca tomorrow. If we don't make CL next year, all the hard work of the last 15 months will be for nothing, because we'll be forced to sell one of the Croats, Icardi, or Skriniar. Making top 4 is a more immediate priority than getting out of the group stage, so when we face a direct rival for a CL spot, we absolutely must take points. It's even more important on this occasion because we have to play teams like Atalanta, Roma, and Juventus in the next few weeks.
Plus, I'm confident we can at the very least draw Barca at home if we have Nainggolan and Messi is still out. 1 point there, 3 from PSV, and 1 from Tottenham guarantees 2nd place. Basically, our targets are easier to achieve if we rest core players at Camp Nou.