Berlin (AFP) – A comedy of defensive errors, including an own goal from Alexander Hack, saw Eintracht Frankfurt progress to the German Cup semi-finals, as they beat local rivals Mainz 3-0 on Wednesday.

A mistake from Mainz goalkeeper Rene Adler gave Frankfurt the lead on 17 minutes. Making his first appearance since he picked up an injury in October, Adler misjudged a backpass from Stefan Bell, providing Ante Rebic with an open goal.

Eight minutes into the second half, Frankfurt doubled the lead, as Hack turned Sebastien Haller’s cross into his own net.

Hack then gave the ball away in his own half just after the hour mark, allowing Omar Mascarell to loft the ball elegantly over Adler for Frankfurt’s third.

Mainz’s misery was compounded in the 82nd minute, when Danny Latza was sent off for a reckless challenge on Marco Fabian.

Frankfurt join Bayern Munich and Bayer Leverkusen in the semi-finals, with Schalke and Wolfsburg set to compete for the final spot in the last four later on Wednesday.