A young fan ran onto the Sporting Lisbon pitch, where Cristiano Ronaldo made a name for himself, before kneeling and kissing the left foot of Barcelona star Lionel Messi on Wednesday.
The supporter skipped past stewards and entered the playing field during Barca's 1-0 win in the Champions League Group D encounter at the Estadio Jose Alvalade, hugged the Argentina captain and kissed his boot.
Sporting fans reacted by chanting the name of Real Madrid star Ronaldo, who began his career at the Portuguese club.
Messi kept his cool and the fan was eventually escorted by a steward off the pitch.
It is not the first time Messi has experienced such a situation as a year ago a supporter did the same in Argentina's 1-0 World Cup qualifying win over rivals Uruguay.
Messi failed to score his 100th European goal on Wednesday in Lisbon but contributed to his side's win.
He had a free kick that was flicked on to the near post by teammate Luis Suarez and it deflected onto the chest of Sporting defender Sebatian Coates before bouncing into the net for an own goal in the 49th minute.
Portugal captain Ronaldo is still revered at Sporting despite having not played for the club since 2003.