LONDON: For 35 minutes on Centre Court Serena Williams was knocked off her stride by a feisty Italian who looked as though she had ripped a page from the American's tennis manual.
Playing in her first Grand Slam quarter-final, unseeded Camila Giorgi went toe-to-toe with the seven-time champion and became the first player to take a set off her so far.
All eyes were on 36-year-old mum Williams to see how she would respond to such a challenge to her supremacy at Wimbledon, where she is unbeaten since 2014.
The answer was emphatic.
Williams raised her intensity level, added some velocity to her groundstrokes and some decibels to her growls and powered back to win 3-6, 6-3, 6-4, a scoreline that was a touch closer than what actually transpired on court.
Williams has fallen 13 times in Grand Slam quarter-finals -- more than in any other round -- but was never panicked.
"It's weird. Sometimes I feel, 'Man, I'm in trouble'. Sometimes I feel, I can fight. For whatever reason, today I was so calm. Even when I was down the first set," Williams who ended with 24 winners and only nine unforced errors, said.
"I never felt it was out of my hands. I can't describe it. I just felt calm. Hoping I can channel that all the time."
With an unprecedented cull of big names at this year's championship, Williams is yet to face a seed, but that will change in the semis where Julia Georges, the 13th seed, awaits.
Williams beat the big-serving German at the French Open last month before injury curtailed her first Grand Slam since giving birth to daughter Alexis Olympia last September.
"That was four or five weeks ago. That doesn't matter. This is a whole new match, it's a new surface, it's everything. We're starting from zero," Williams said of Thursday's assignment, her 11th Wimbledon semi-final.
Considering what she went through during a traumatic labour nine months ago, since when she has played only a handful of matches, Williams's physical condition has been impressive.
"I'm not tired at all," she said. "When I was out there today, not once was I out of breath.
"Maybe it's because there weren't many long points, but, hey, got to look at the positives, right?"
There were many of them -- not least her mighty serve.
She lost only four points on it in the opening set, all of them in the sixth game when a courageous Giorgi rifled a backhand deep into enemy territory to snatch a break out of nowhere, setting the Centre Court crowd abuzz.
It stung Williams and she went 0-40 in the next game, but Giorgi showed real steel to hold for a 5-2 lead.
When Williams hit a forehand long to hand Giorgi the set, it looked possible that her quest for a 24th and possibly most remarkable Grand Slam title might be in peril.
Even when Giorgi held for 1-1 in the second with an ace though it seemed a matter of time before the match turned.
The next time Giorgi served, it did. Williams unleashed some savage forehands that rocked the Italian then secured her first break with a crosscourt winner.
There was a controlled fury about Williams's play, and when she conjured an off-balance backhand winner to break in the third game of the decider, the outcome was inevitable.
Giorgi hung in gamely to at least make Williams serve to reach her 35th Grand Slam semi-final and 11th at Wimbledon.
Williams stepped up to the line at 5-4 and brought up match point with an ace before completing victory, her 91st here, when Giorgi pushed a forehand into the net.