Guimaraes finished 3rd in the Portuguese League last season and will face the qualifying stages of this coming season's Champions Leauge. They are the "home team" in this tournament being from Portugal but they are actually based in the North West of the country and not from the Algarve region.
The four team tournament involves Guimaraes, Cardiff City, Middlesbrough and Celtic. Each team players two games. Cardiff face Celtic on Thursday and will not face Middlesbrough at all.
The games are played back to back. Tonight it's Cardiff v Guimaraes (7:15pm) followed by Celtic v Middlesbrough (9:30pm).
There is no TV coverage of tonight's game but Cardiff v Celtic on Thursday (9:30pm) is live on Setanta Sports (surely our first ever live pre season friendly?)