PARIS- The ball landing at Barbora Krejcikova’s feet on match point appeared to come down behind the baseline.

The linesman thought so and called the shot long. A TV replay confirmed as much, and the unseeded Krejcikova was so sure she raised her arms in triumph to celebrate a berth in her first Grand Slam final at the French Open.

Chair umpire Pierre Bacchi disagreed. He reversed the call, sparking a fresh round of debate about video replay and briefly delaying Krejcikova’s victory.

Tennis was spared an unjust result five points later, when she hit a backhand winner to close out the biggest victory of her career. The Czech saved a match point midway through the final set and outlasted No. 17-seeded Maria Sakkari of Greece, 7-5, 4-6, 9-7.