Kevin Constant had a banana thrown in his direction in Milan's Serie A fixture at Atalanta - the second such incident in a matter of weeks after Barcelona's Dani Alves was targeted in a similar fashion at Villarreal.
In Russia, Zenit's game with Dinamo Moscow had to be abandoned in the closing stages as home fans invaded the pitch at the Stadion Petrovskij.
Andre Villas-Boas' men came into the clash knowing victory would guarantee they entered the final round of Russian Premier League fixtures as leaders.
However, with their side 4-2 down and seemingly on course to lose their grip on first place, home fans charged into the area behind the away goal in the 87th minute of the match.
As stewards struggled to contain the on-rushing crowd, referee Sergey Ivanov ordered both teams from the field.
Tempers flared among the players as they left the pitch, and a section of the Zenit support made their way onto the playing surface.
One fan appeared to direct a punch at Dinamo's Vladimir Granat, and Blatter took to Twitter to express his disappointment at both incidents.
"Racism, and games stopped/abandoned due to acts of hooliganism. Each Federation needs to act. Sanctions are available & HAVE to be applied," he said.
There were also reports Portuguese CSKA Sofia winger Toni Silva was the victim of racial abuse in the Bulgarian league at the weekend.
