Combined goals against Top 6 opponents in la liga (Barcelona, Real, Atletico, Valencia, Sevilla, Bilbao and Villareal) Chose the bolded teams because they are the only team in la liga who when the big two visit their away ground, theres a legitimate chance of an upset. (On average over the course of both their careers)
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Combined goals against any european opponent who would be considered a big club. Consistently in Europe, does well in their league and has some historical sense of success about them.
Messi- 184 goals total versus the 6 top La liga teams and Arsenal, AC Milan, Manchester City, Bayern Munich, PSG, Chelsea, Roma, Man Utd, Juventus.
Ronaldo- 169 goals versus the top 6 la liga teams and Spurs, Bayern Munich, Juventus, Dortmund, Arsenal, Roma, Man City, PSG, Liverpool, Man Utd, Ac Milan, Chelsea, Inter Milan (includes goals from ronaldo's time in PL)