In the deciding game trailing at 4:8, struggling with Groth's serves most of the match, Dan Qiu called service fault using TTR, and he succeeded!
The loss of the point rattled Groth, he lost next 4 points. Then, Dan called the TTR challenge again, and he succeeded again! Then Dan claimed the coming-back victory at 11:9.
Groth tried to challenge the TTR but was not allowed. He must have bitter taste after the match. He sure would feel he was defeated not by Dan but TTR.
Is this the first case that a player used TTR challenge system twice in a match and succeeded? It might be the turning point that players will use it more aggressively and frequently.
Watching the slow motion of the TTR, even though the contact point of rubber brushing ball was clear on both cases, the balls were indeed hidden by Groth's head momentarily on the way down before the contact point. If that's a violation of the legal service rule, I'll say quite many pros will face the same challenge.