By the time we play them, February 22, we will probably be out of the race for top 4, since we'll face Napoli, Milan, Roma and Atalanta (3 of them away) in Serie A in the opening 6 rounds of the 2nd part of the season.
My point is, we won't underestimate Villarreal, not only because they won EL half a year ago, but also because we'll have nothing else to play for in Italy and we'll be fully concentrated and motivated for these two matches against them.
Now, will we be good enough to eliminate them...? If we have a full squad, it's 50-50 imo.