I claim the ornamental design for a tennis game scoreboard, as shown and described.
FIG. 1 is a perspective view of a tennis game scoreboard, showing my new design with a plurality of scoring tabs all in a retracted position;
FIG. 2 is a front elevational view of FIG. 1;
FIG. 3 is a rear elevational view of FIG. 1;
FIG. 4 is a right-side elevational view of FIG. 1;
FIG. 5 is a left-side elevational view of FIG. 1;
FIG. 6 is a top plan view of FIG. 1;
FIG. 7 is a bottom plan view of FIG. 1;
FIG. 8 is a perspective view thereof, illustrated with the plurality of scoring tabs all in an extended position.
FIG. 9 is a front elevational view of FIG. 8; and,
FIG. 10 is a rear elevational view of FIG. 8.
It is understood that the shading on the tabs on one side of the design in FIGS. 8-10 represent a contrasting surface to the shading of the tabs on the other side of the design.