At IFA 2026 in Berlin, a quiet but consequential threshold was crossed in the world of sport: ACEMATE unveiled the S10 Pro, a tennis robot that no longer merely feeds balls but moves, reads, and responds like an opponent. Where the ball machine has long served as a solitary stand-in for human practice partners, this machine introduces computer vision, court mobility, and tactical decision-making into the equation — suggesting that the boundary between equipment and companion is beginning to dissolve. The question it raises is not simply whether technology can simulate a tennis partner, but wha