With three group games remaining, Team USA is in third place in its eight-team group. The top four teams from each group move on to the quarterfinals.
Jimmy Howard made 23 saves and five different players scored for the United States. Thompson's goal gave the Americans a 3-2 lead late in the second period.
Finland and Canada hold down the top two spots in Group H -- so named because all the group games take place in Helsinki. The Americans have eight points with Slovakia and Switzerland tied for fourth with six points each.
Sweden and Russia are tied for the lead in Group S (Stockholm), followed by the Czech Republic and Latvia.
The Americans meet Kazakhstan Friday and have group games remaining against Finland and Switzerland.