Real Madrid's Roberto Carlos could face disciplinary action for retaliating against Bayern Munich defender Martin Demichelis moments before the Brazilian scored in their Champions League match on Tuesday, UEFA said.

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"We've opened a disciplinary case against him and a decision will be announced by about 5 pm on Monday," a spokeswoman for UEFA's disciplinary panel in Nyon, Switzerland said on Thursday.

"There are many possible sanctions available. The most likely would be a suspension for one or several matches."

Television replays showed Roberto Carlos swiping at Demichelis's face after being fouled by the Bayern defender. It was not clear whether he connected with the Argentine or not. The Norwegian referee Terje Hauge did not punish Roberto Carlos.

The Brazilian's long-range free kick with seven minutes left squirmed under the body of goalkeeper Oliver Kahn to level the match at 1-1 after Roy Makaay had given Bayern a 75th-minute lead. The second leg is at the Bernabeu on March 10.