Soderling defeated James Blake 5-7, 6-3, 6-0 and Johansson upended Bobby Reynolds 6-3, 2-6, 6-3 assuring the Swedes a win in the best-of-three Red Group series with the United States.
Both teams entered Thursday with 2-0 round-robin records, leaving the Sweden-U.S. pairing to decide the group winner.
Sweden, which last won the team title in 1995, heads into Saturday's finals but won't know its opponent until after Friday's Blue Group round-robin play ends. All four teams in that group entered Thursday tied 1-1.
The Blue Group teams have their second singles matches and a doubles match to go Friday before a final opponent for Sweden is determined.
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