The goal is to maintain the readiness and fitness of players ahead of the start of competitions.
The delegation included Bundesliga International CEO Robert Klein and DFL’s Head of Intl. Affairs Dr. Marc Lenz.
Al Rayyan's victory means Al Sadd are all but out of the title race.
Al Sadd are third in the standings with 32 points, seven behind leaders Al Duhail and three adrift of Al Rayyan.
Al Ahli twice came from behind to play out a thrilling 2-2 draw with Qatar SC.
The result was not of much help to both teams who are at the bottom of the table.
Leaders Al Duhail face Al Sailiya in another big match.
The win helped Al Sailiya increase their tally to 23 points, just two behind fourth-placed Al Gharafa.
Sadd stay third in the standings, seven points behind leaders Al Duhail.
The win helped Al Duhail maintain their four-point lead at the top.
Duhail lead Qatar Stars League table with 36 points, four ahead of second-placed al Rayyan.
Title challengers Al Sadd and Al Rayyan both dropped points.
Xavi Hernandez coached Sadd remain third in the table with 31 points.
The Lions are on 32 points, but leaders Duhail can consolidate their position with a victory against Al Wakrah on Saturday.
Arabi stay fifth with 20 points, just one ahead of Al Wakrah.