ɡˈɪlɚmˌoʊ ɑːtʃˈoʊə wʌz ɛkspˈɛktᵻd təbi ðə stˈɑːɹɾɪŋ kˈiːpɚ fɔːɹ mˈɛksɪkˌoʊ æt ðə tˈuː θˈaʊzənd tˈɛn wˈɜːld kˈʌp bˌʌt ɪn ɐ sɚpɹˈaɪz mˈuːv, pˈɛɹɛz wʌz kˈɔːld ˌʌp ænd plˈeɪd æz ðə stˈɑːɹɾɪŋ ɡˈoʊlkiːpɚɹ ɪnðə tˈʊɹnəmənt.
Guillermo Ochoa was expected to be the starting keeper for Mexico at the 2010 World Cup but in a surprise move, Pérez was called up and played as the starting goalkeeper in the tournament.