I mean stupidity of the idea that Spanish league teams are terrible in defense has been proven so many times it is unfunny. Why aren't Sevilla, Valencia, Celta, Getafe, Espanyol, Athletic Bilbao, Malaga, Villarreal conceding 3-4 goals every time they face mighty Premiership teams in Europe? Look at the list of La Liga teams that played in Europe in the past 10-20 years. They all did VERY well, so well that La Liga held historical lead over other leagues in UEFA coefficients.
Here are some examples:
Getafe 2007-2008 season:
Tottenham Hotspur 1 – 2 Getafe
Getafe 1 – 2 Hapoel Tel Aviv
AaB 1 – 2 Getafe
Getafe 2 – 1 Anderlecht
R32 Greece AEK Athens 3–0 1–1
R16 Portugal Benfica 1–0 2–1
QF Germany Bayern Munich 3–3 (aet) 1–1
Lowly Getafe beat Benfica, Tottenham and played 2 draws vs mighty Bayern and were only knocked out due to the away goal rule!
Espanyol 2006/07
R32 Espanyol-Livorno 4-1 overall
R16 Espanyol-Maccabi 4-0
R8 Espanyol-Benfica 3-2
R4 Espanyol-Werder 5-1
UEFA Cup final Espanyol-Sevilla 2-2
Malaga 2012/2013
Finished 1st place in their CL group ahead of AC Milan (!, won and drew vs them), Anderlecht and Zenit
R16 Malaga-Porto 2-1 overall
1/4 Malaga-Borussia D 2-3
They went out vs Klopp's Borussia D in the stoppage time.
When we talk about La Liga teams' European performances, most people dismiss the record saying this is due to Barca and Madrid. In realty, Spanish midtable teams that are now seen as "cannon fodder" by some were never easy to play. Hardly ever they rolled over and were pumped by 3, 4 or 5 goals. Meanwhile, there are about 1000 excuses every time a Premiership team fails against some noname team.