A Moscow court on Monday handed down a 15-day jail sentence on one of four people who interrupted Sunday's World Cup final between France and Croatia when they ran onto the pitch wearing fake police uniforms.
The judge also banned Veronika Nikulshina from attending sports events for three years.
The pitch invasion by members of 'Pussy Riot' punk band was a brazen act in Moscow's Luzhniki stadium in front of Russian President Vladimir Putin.
Three others were due to be sentenced later on Monday.
Olga Kurachyova, one of the four who raced onto the pitch dressed in police-style outfits, said the stunt was meant to promote the freedom of speech and condemn the world footballing body, FIFA.
Croatian defender Dejan Lovren, who pushed the male intruder aside on the pitch, told reporters the incident had interrupted the game at an important moment for his team.
"It is a pity that we disrupted the sportsmen," Kurachyova told reporters on Monday.
"FIFA is involved in unfair games unfortunately. FIFA is a friend of heads of states who carry out repression, which violate human rights.
The match, watched from the stands by Putin and the French and Croatian presidents, was briefly halted early in the second half, but resumed after 25 seconds.
France went on to win the final 4-2.