Shortly after finalising the paperwork of his transfer to Dortmund over the weekend, Matthews was drafted in the team for their UEFA Youth League clash on Tuesday evening.
The 18-year-old flew out to Madrid with his teammates to face Atletico Madrid in the Under-19 version of the UEFA Champions League.
The Ajax Cape Town youth graduate started the tie at the Estadio Cerro del Espino, which kicked off at 17h00 (SA time).
However, he lasted only 27 minutes in his first appearance as he was taken off just two minutes after his side went 1-0 down.
It appeared a tactical substitution as coach Benajamin Hoffman made a second change just one minute after they went 2-0 down in the 34th minute.
The BVB eventually succumbed to a 4-0 defeat and currently sit bottom of Group A, with just one point from four games.
Tashreeq Matthews (bottom right) made his official @BlackYellow debut this evening, but was substituted out after 27 minutes as they went on to lose 4-0 to Atletico Madrid U-19 in the @UEFAYouthLeague.— Chad Klate (@CKlatey) November 6, 2018
(???? @BVB) pic.twitter.com/fQmpW66rmC
Ateltico top the group with nine points, level with French side Monaco, while Belgian outfit Club Brugge are in third place with four points.
Matthews could make his U-19 Bundesliga debut when Dortmund take on Rot-Weiss Essen on Sunday at 12h00 (SA time).