While the victory was Mexico’s second at a FIFA U-17 Women’s World Cup, defeat leaves their opponents facing an uphill battle to avoid being eliminated at the group stage for the third consecutive edition.
Christopher Cuellar’s team then struck the crossbar 11 minutes later, Perez the unlucky player. Perez went close again shortly after, sending her cross-shot just wide of the post.
The Kiwis came to life midway through the opening period when a set-piece from Emma Fletcher drifted narrowly over the bar. Luz Duarte was denied by the New Zealand defence after an impressive dribble on the half-hour, but the breakthrough arrived five minutes later.
Perez rose highest to head home a corner-kick past Alfeld and give Mexico the lead, which they showed no signs of surrendering before the break and indeed held onto throughout the second half.
Alfeld kept New Zealand in the match with saves from Samantha Arellano and Taylor Alvarado, but their misery was compounded by an injury to Megan Lee and there was no way back.
The Mexicans are back in action on Wednesday against Brazil, while New Zealand face Japan later the same day.