Can You Play Singles in Wii Sports Tennis? No – Doubles Only.

The original Wii Sports Tennis only supports doubles matches (2 vs 2). Singles (1 vs 1) is not an option in any mode.

For Singles Tennis on Wii

• Wii Sports Resort: Includes "Swordplay" but not tennis singles. Wait—Resort has Table Tennis (Ping Pong) which is 1v1.
• Mario Tennis Open (3DS) / Mario Tennis Aces (Switch): Full singles tournaments.
• Top Spin 4 / Virtua Tennis 4 (PS3/360): Realistic singles career.
• Grand Slam Tennis (Wii): MotionPlus singles (EA, 2009).

If you want 1-on-1 tennis with Wii Remote motion, Grand Slam Tennis is your best bet on Wii. Otherwise, upgrade to Switch/3DS/PS3/360 for dedicated tennis games.