Italy's Fabio Fognini has apologized for using an ethnic slur toward Serbian opponent Filip Krajinovic during a second-round loss at the Hamburg Open.

A video of Fognini showed him muttering the Italian word `zingaro', meaning gypsy, while he had his back to Krajinovic during Wednesday's match.

After it was picked up on social media, Fognini tweeted: ''I made a mistake. I didn't want to offend anyone. ... I know Filip very well and anyone who plays sports knows that at times you get carried away saying things that make no sense.''

Krajinovic, a 149th-ranked qualifier, won 6-4, 6-0 against the defending champion and second seed.

The temperamental Fognini also broke his racket in half by stepping on it as he headed to a changeover midway through the second set.