In the final the Germans were four goals up before Sarah Kelleher pulled one back on half-time. Denise Klecker restored the Germans' four-goal advantage before Slough conceded two further goals.
Nick Thompson, the Old Loughtonians player-coach, scored his second goal in injury time to put his side into the semi-finals of the EHA Cup with a 3-2 win against Teddington.
With the former Great Britain captain Jason Laslett controlling the midfield, Teddington had levelled matters with two goals from James Wallis, only to concede the penalty corner in the dying seconds.
In the other cup games, Cannock, with goals from Paul Edwards (2) and Ben Sharpe, shot into a 3-0 interval lead against First Division Lewes. The Sussex club pulled back to 3-2 before Cannock won 4-3.
Southgate had an even better start, going 5-0 up before Hounslow opened their account. With 18-year-old John Grice scoring twice, Southgate went into the interval leading 7-1, settling for a final 8-3 scoreline. In the remaining game Reading accounted for Canterbury 5-2.Reuse content