Bernard Tomic stunned Tommy Haas and the commentators with an incredible backhand pass in his straight-sets victory in Germany.
The Australian took out the first set 6-4 and continued his tear as the match went on.
At 15-all in the first game of the second set Haas served to Tomic's forehand, with a long volley from the German veteran then appearing to win him an easy point.
But Tomic chased it down and swung a one-handed backhand down the line. Somehow it gave Haas no chance, even though he was comfortably in the right service box at the time.
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"No, he hasn't! He has. Has he?" one commentator gasped.
"Yeah, he has. He loved that one," the other quiped as replays showed Tomic reacting to the point.
"He has no right to hit a shot like this, one-handed, on the run."
The 24-year-old Tomic had won just six of his 18 matches in 2017 going into the Halle opener against Haas.
His tennis wasn't flawless but it was easily the best he has produced all year as he failed to give Haas, who last week beat Roger Federer in Stuttgart, a sniff.
Tomic didn't face a single break point in the match as he mixed up the speeds on serve, sending down seven aces.
The Queenslander was also dominant from the back of the court, hitting deep flat forehands to push Haas onto the back foot, forcing errors from the German as he unloaded 33 winners for the match.
Haas was far from happy with his own performance against Tomic.
"I'm not that satisfied with the way I played today, especially in front of a Halle crowd, but that's how it goes sometimes," Haas said.
"My body wasn't where I needed it to be the last few days to give it a real good go. He was also a tricky opponent."
Tomic will face a big challenge in the second round in the form of Richard Gasquet.
The Frenchman owns a 6-2 head-to-head record over the Australian, but they have split their two matches on grass.