Barcelona striker Lionel Messi lost his cool in a friendly against Roma on Wednesday.

The mild-mannered Argentine, who's widely regarded as the best footballer in the world, head-butted and then grabbed the neck of Roma defender Mapou Yanga-Mbiwa after a blown whistle in the 35th minute. It was not known what Yanga-Mbiwa might have said to cause Messi to act the way he did. Both players received yellow cards.

Messi netted a goal a few minutes later and Barcelona would go on to win 3-0.