In Villarreal's defense struggle, they have struggled to concede fewer goals than their opponents in recent matches. This is a problem that has been plaguing the team for some time now and has led to a decline in their overall performance.

One reason why Villarreal has struggled with conceding fewer goals is due to several factors. Firstly, the team has not had the right amount of quality players on the pitch to score goals consistently. Secondly, the defensive line has struggled to contain the opposition's attackers effectively. Finally, Villarreal's defenders have not been able to defend well enough against the opposition's attacks.

To address this issue, Villarreal needs to invest more resources into training and development of its defensive players. The team should also focus on improving the consistency of their attacking performances and developing stronger defensive lines. Additionally, Villarreal can improve their defensive tactics by using different formations and strategies to counter the opposition's attacks.

Overall, Villarreal's defense struggle is a significant challenge that needs to be addressed before they can continue to perform at a high level. With proper investment and improvements, Villarreal could potentially regain their previous form and become one of the top teams in La Liga.