Slovenia beat 10-man Algeria 1-0 to claim its first ever World Cup victory and the top spot in Group C. Komac came on as a substitute in the final minutes.
"We took three points in the first game," the 30-year-old Komac said after practice Tuesday. "No one looks at us as small anymore. Now we can only go forward like this, because we are leading the group."
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The U.S. and England have one point each after their 1-1 draw.
Komac said there's "a good feeling" in the squad going into Friday's match against the U.S.
"We are going to win this match," he said.
With a population of just over 2 million, Slovenia is the smallest nation in the World Cup, but its national team has upset bigger rivals before. It finished second in its qualifying group ahead of the Czech Republic and Poland and stunned Russia in a two-match playoff to enter its second World Cup.
Slovenia already is doing better than in 2002, when it lost all three group matches.
Captain Robert Koren secured the victory Saturday against Algeria with a long-range shot in the 79th minute that goalkeeper Fawzi Chaouchi misjudged and allowed to bounce into the net off his arm.
Slovenia produced few scoring chances against Algeria, but fielded a strong defense that the North Africans couldn't break down.
Komac said Slovenia is not going to change it's strategy when it faces the Americans.
"We are playing our style of football and we'll continue with that and we can beat the U.S. with that style," he said.
Slovenia will advance to the second round if it beats the U.S. at Ellis Park in Johannesburg.
Look for Tim Howard in the net when the United States takes on Slovenia Friday. The American keeper's bruised ribs are improving and he's expected to be ready to go for the second U.S. match.
Howard took a boot in the ribs during Saturday's 1-1 tie with England. He needed a painkilling injection at halftime, but managed a number of big saves in the second half to preserve the draw. Slovenia leads Group C after an opening match win, while the United States and England are tied for second with a point apiece.