After winning the first set, Stosur lost the match in a tight battle, 3-6, 6-3, 6-4.
The pairs competition was a tight battle between the two top Russian teams.
The contest Tuesday night was a tight battle throughout, and at times an emotional one.
The tourists had survived another tight battle under the leadership of Hassett.
It was a tight battle for 60 minutes with each team scoring just once.
Those top 10 will be separated by only 45 points, setting up a tight battle in the final 10 races.
The tight battle thrilled a crowd of 17,049 that thought it would be headed for the parking lot long before it finally left.
"We're in such a tight battle that every lap, every position is so important."
The mayor is up for re-election next month in a tight battle.
The final round was a very tight battle, except for the Americans.