This Pogba left huge gap in defense in league cup is narrative made by the English pundits. The problem with our defense was the Mata had a meh game. Perhaps due to his family issue before the game. Bertrand & Redmond combination couldn't be handled by Valencia himself. Then our CB pair had below standard game. Our tactic was similar to that of EL final that we tried to stiffled them by man marking them in midfield and forced them go long to Gabbiadini who should be taken care well by our CBs, especially Smalling for his man marking style. It failed.
You must not watch Pogba enough to say he always wants to get involved all over the pitch. He can play very disciplined. If anything as I put it in previous post & many time regarding different matters, many positions in our teams underperform throughout season leading to some players having to do too much on their own. Pogba has football brain to know when & what to do. It's not theory or anything like that, toward the end of the season, his defensive game visibly improved. The Ajax game (not midfield 2, but Pogba played deep in double pivot role for huge part of game) he man marked perfectly. VS England in that friendly, he outperformed Kante defensively IMO.