A blunder from 43-year-old Pachuca goalkeeper Oscar "Conejo" Perez helped Necaxa to a 2-1 victory on Thursday in the Apertura 2016 quarterfinal first leg in Estadio Victoria.

Former Mexico international Perez was well-placed to catch a soft shot from distance from Felipe Gallegos in the 33rd minute, but dropped the ball onto his own foot and deflected it into the net to gift Necaxa the lead.

Recently-promoted Necaxa pushed for a second in the first half against the reigning Liga MX champion, but Pachuca came out reinvigorated after the break and started to force the game.

Pachuca's reward came in the 66th minute, when some neat work by Mexico international Rodolfo Pizarro down the right, set up Victor Guzman to hammer home the equalizer from the edge of the area.

It was a vital away goal for Pachuca, but Necaxa came back and Claudio Riano slid the winner past Perez five minutes from the end.

In second half injury time, Chile international Edson Puch drove inside from his left wing position and almost extended Necaxa's lead with a curling shot that finished just wide of the post.

Necaxa came into the series as the outsider, but will go through to the semifinal with a draw or victory in Sunday's return leg in Estadio Hidalgo.