The La Liga expert and former Red warned United not to underestimate the strength of a side who have consistently defied expectations over the last two seasons.
“United can't afford to take them lightly,” Gibson insisted. “They're going to play like an away team at home. They'll look to play on the counter-attack, which they're good at.”
Although United have endured some tough ties against Spanish opposition in the last decade, the Reds comfortably dispatched Granada's La Liga competitors Real Sociedad in the round of 32.
Gibson described La Real as “naïve” in their approach and backed Granada not to make the same mistakes.