Sofia - An own goal by Bulgaria centre back Nikolay Bodurov gave Croatia a 1-0 victory in a Euro 2016 Group H qualifier marred by unruly behaviour by fans of both teams at the Vasil Levski stadium on Friday.
The visitors struck after 36 minutes when the powerfully-built Bodurov turned the ball into his own net as he tried to clear Ivica Olic's header from Ivan Rakitic's right-wing cross.
The match was interrupted for a few minutes midway through the first half as rival supporters threw fireworks at each other and a number of flares were hurled from the stands.
Bulgarian Football Union president Borislav Mihaylov, who is also a UEFA executive committee member, said he would not be surprised if European soccer's governing body punished his team for the crowd disorder.
Italy and Croatia are joint top with six points from two matches followed by Bulgaria and Norway on three apiece.
"We fully deserved this victory," Croatia coach Niko Kovac told reporters.
"We were the better team, we dominated in the first half and then we had some problems in the second but I'm pleased with my team because it was a very important victory."
Croatia started well with midfielder Ivan Perisic having two shots deflected over the bar before Bodurov's blunder.
Bulgaria's 4-2-3-1 formation, featuring Ilijan Micanski up front, looked toothless for long periods of the opening half and they failed to create a single chance.
Luboslav Penev's team almost levelled however when midfielder Vladimir Gadzhev sprang the offside trap only to curl his shot wide of the post.
At the other end Bulgaria keeper Vladislav Stoyanov saved Marcelo Brozovic's thunderous shot from the edge of the penalty area.
Bulgaria pressed hard for an equaliser after the interval with substitutes Georgi Iliev, Andrey Galabinov and Aleksandar Tonev creating good chances while Croatia were forced to rely on swift counter attacks.
On Monday, Croatia host Azerbaijan (zero points) and Bulgaria visit Norway.
"We have to forget this match as quickly as possible," said Bulgaria captain Ivelin Popov who wore a protective mask after fracturing his cheekbone last month.
"Tomorrow we'll do an analysis and we'll begin to prepare for the Norway game."