Nigel Hasselbaink has lost his appeal against a red card, making history as the first player to go through new streamlined disciplinary procedures.
The St Mirren striker was sent off for violent conduct after striking Dundee United defender Paul Dixon with his trailing arm during Saturday's draw.
Buddies general manager Brian Caldwell said: "We are very disappointed.
"We felt the evidence that was produced to the members of the panel would have been enough to exonerate Nigel."
Hasselbaink will now miss Saturday's Scottish Premier League meeting with Motherwell and the following weekend's match against Hibernian.
The Scottish Football Association's new procedure ensured that a decision about the appeal was made before St Mirren's next competitive game.
However, the Buddies' pleas were dismissed by the first hearing of the new judicial panel.