He was meant to be flying the flag for Denmark but instead Nicklas Bendtner decided to advertise an Irish betting company in the moments after he scored against Czech Republic.
On Monday, UEFA showed they wouldn't be taking the indiscretion lightly by banning him for one 2014 World Cup qualifying match following the brief act.
The UEFA's disciplinary panel found the player guilty of "improper conduct" for revealing an unofficial sponsor's name on his underpants and fined the 24-year-old $126,000.
Bendtner can appeal the decision.
The punishment rules the striker out of Denmark's opening World Cup qualifier at home to the Czech Republic on September 8th.
Bendtner's financial penalty is the second-highest imposed by UEFA at Euro 2012. The Russian football association were fined $151,000 after their fans attacked stadium stewards in Wroclaw following the team's group game against the Czech Republic.
Bendtner raised his shirt and lowered the top of his shorts slightly, revealing the name of a betting firm across the top of his underpants, after scoring his second goal in a 3-2 loss against Portugal last Wednesday.
UEFA tournament rules bar ambush marketing by unofficial sponsors or advertising on players' kit.
The laws of football managed by FIFA relating to players' equipment also state the bottomline is players "must not reveal undergarments showing slogans or advertising."
Bendtner was also separately disciplined by the Danish Football Association for flouting team policy. The association has official ties to a rival gambling company.
Denmark were eliminated from Euro 2012 on Sunday after losing 2-1 to Germany.
While neither the team nor Bendtner were pants at the tournament, it is pants that are making the headlines.