Borussia Dortmund's famously excellent fans were at it again ahead of last night's Europa League clash with Porto.As the teams were walking out, the German side's supporters unveiled a huge sticker album chronicling the trophies they've won: the Champions League was in place, as were the UEFA Cup Winners' Cup, Bundesliga, and DFB-Pokal.But there was a space left open for the Europa League – a tournament the club has never won, having twice lost in the final (when it was known as the UEFA Cup).Then a giant sticker packet rose from nowhere, with the missing Europa League sticker poking out the top. The message was clear: this trophy belongs in our collection.And to make certain the team knew how important it was, the Europa League stickler was a shiny – the most prized and wondrous of stickers.Dortmund took a step towards that goal by beating Porto 2-0. However this was only the first leg of the round of 32; the sticker may be in the packet, but they're nowhere near ready to peel it off just yet.