In the present studies, the Leuven Tennis Performance Test (LTPT), a newly developed test procedure to measure stroke performance in match-like conditions in elite tennis players, was evaluated as to its value for research purposes. The LTPT is enacted on a regular tennis court. It consists of first and second services, and of returning balls projected by a machine to target zones indicated by a lighted sign. Neutral, defensive, and offensive tactical situations are elicited by appropriately programming the machine. Stroke quality is determined from simultaneous measurements of error rate, ball velocity, and precision of ball placement. A velocity/precision (VP) an a velocity/precision/error (VPE) index are also calculated. The validity and sensitivity of the LTPT were determined by verifying whether LTPT scores reflect minor differences in tennis ranking on the one hand and the effects of fatigue on the other hand. Compared with lower ranked players, higher ones made fewer errors (P < 0.05). In addition, stroke velocity was higher (P < 0.05), and lateral stroke precision, VP, and VPE scores were better (P < 0.05) in the latter. Furthermore, fatigue induced by a prolonged tennis load increased (P < 0.05) error rate and decreased (P < 0.05) stroke velocity and the VP and VPE indices. It is concluded that the LTPT is an accurate, reliable, and valid instrument for the evaluation of stroke quality in high-level tennis players.