Mauro Bergamasco will miss Stade Francais' Heineken Cup quarter-final with Leicester on Sunday after losing his appeal against a four-week ban.
Bergamasco won the man of the match award against Wales
The Italian flanker hit Wales captain Stephen Jones and was suspended by the Six Nations disciplinary committee, who have upheld the original decision.
Bergamasco was cited for foul play after Italy's 23-20 win with Jones forced to leave the field for stitches.
He will now complete the rest of his suspension which ends on 9 April.
The 27-year-old escaped punishment during the match and turned in a man-of-the-match performance in his team's historic win, scoring the crucial 77th-minute try.